I received a job offer, but even the text of the vacancy and other conditions are unknown, what should I do?

Question

Career in IT

all actors, names, etc. have been changed.
Who am I: looking for a job as an electronics programmer, 13+ years of experience, as a programmer 15+ years, but I can start working fully with NG.
Who issued the preliminary offer: one very large company, very widely represented on Habré, is engaged in outsourcing and the staff works with foreign customers, as I understand it directly. BUT Company profile in 99% web and enterprise. and does not match my area from the word at all
How my vacancy is presented:on their website in the other section, the text of the vacancy is one line, for example: "accelerometer filtering programmer" - yes, yes, literally one line, no information about the platform, no toolchain, no environment, nothing at all. even the level is incomprehensible, student / pro, etc., no full time either.
course of events:
three weeks ago.
they themselves offer me to consider a vacancy from this one line, I agree to talk with their staff manager (not a recruitment agency), we talked, everything is ok, on-duty questions about whether he worked with accelerometers and hardware. Why am I looking for a job, etc. my questions about the details are answered with "breakfasts" and "let's go through those interviews." But they agreed on the salary and it is clearly not for a student and suits me.
after a couple of days of those interviews:
general questions and tasks about the thinker, a more detailed clarification of my those experiences, and a control task about! SOUND!, ok, I told them, they liked it, again, "uh, where are the details?" - "poizzhe", okay. I don't know anything about the project yet.
two weeks ago:
they get in touch, they say that they liked me very much, and most likely they take it, but they already promise to tell about the project. okay, I’m talking, but the communication didn’t work out - the other person demands to sign an NDA and promises to send a description of the project and technical specifications and datasheets in response. NDA signed and sent. silent.
after a couple of days they get in touch and say that it is necessary to pass a trial oral interview in English, "I warned right away that it was bad with him" "let's try anyway", it turned out to be really bad. They are very surprised at the end they give out "the customer may have Russian speakers, we have clarified this, we continue the process." In response, for the second time, I firmly demanded that the details are needed and that it has already been signed. but they again ignored / forgot and so on.
disappeared for a while
on Monday, they suddenly showed up and urgently demanded to remake my CV in their way and their forms. ok, I dropped everything, urgently made these 5 pages within two hours ...
on Tuesday they sent me my CV, almost half redone (a lot of things were embellished so that the marketer would envy and the pan would not be enough to collect so many "pastas"), asked me to practice my English and generally prepare for an interview with a foreign customer ... oops ...
this morning they send a preliminary offer for an even higher salary (also from one line, by the way).
I explain to them that there is no object of the transaction - the text of the vacancy. I don’t know the subject of the transaction, what kind of customer I don’t know, there aren’t even obligations of the parties - I don’t even know what I will code on and whether I can code, and I haven’t seen the TK in my eyes
and for the third time I strictly and for the last time warn that if I all these texts will not be sent, then I apologize and refuse this preliminary offer before the interview with the customer.
and they are suddenly silent for the whole day. although before that they called me 10 times a day this week and answered within minutes.
having a preliminary offer, I have the following result:
1. the object and subject of the transaction are not known, my duties and required skills are also unknown.
2. Working conditions. s/n suits me.
3. there is no vacancy text. there are only snippets of "write these three lines in the resume summary", they are clearly from the text of the vacancy in the must have block.
4. There are doubts that I fit their requirements. those interviews were not from that area at all.
5. hellish confusion on their part in the process of this whole thing, I have dozens of people from their company added to Skype and no one really knows anything. everyone says tomorrow, only after nda, and so on,
6. this is not their profile.
7. They should have closed the vacancy yesterday - this can explain their haste.
8. I did everything as they wanted and as quickly and politely as possible.
9. it is not clear how I will work with representatives of a foreign customer, they insist "nothing will suddenly work without English" - I feel a stranglehold on their part, which is also suspicious
now in the evening, finally a message came that they could not send anything by mail and did not do it what I asked, but they offer to talk more tomorrow or this week.
question: what to do? make concessions and continue talking or just refuse because of such a mess? the money is good and the place of work is prestigious and the schedule is normal, but I don’t need money yet - I don’t need to get a job urgently.

Answer 1

No concessions You can even ask for a
surcharge for nerve treatment or compensation for the time spent for their mess time spent on negotiations - recalculate in $ At their next call, ask the person who will make a decision on your acceptance to call you back and further conversation will be only with him and only on the merits 4. Judging by the movements, the company found a vacancy, the amount of which so aroused that they decided to do something other than their own. In short - they are responsible for your competence 5. Apparently the fee for your head is much more than the standard amount ~ 1-2 months salary 6. You are great
7. Rather, there is competition between them and someone else
9. Most likely you will have to finish learning English on the spot
Do not be surprised if you are suddenly offered a mandatory relocation or frequent business trips to the place

Answer 2

If you subscribe to complete uncertainty, you can lose much more than you find. Well, get ready for the fact that it will be even worse in terms of the organization of work. It can get better too, but it's foolish to hope for it.

Answer 3

Yes, they are trying to sell some project with you. For this, the team is presented to a potential customer. If they sell, they make you an offer, if they don’t sell, they will apologize and that’s it.
Don't sweat it, go with the flow. If the project is sold, discuss everything again, and you will be told all the details. Then you will make a decision.