Got stuck in the development process. How to get out of this situation?

Question

CMS

Hello, friends.
I am a designer. Now I'm making a website for an English teacher. I ask for help from all those who are not indifferent to web development. I can not understand what the problem is, I will state the essence below.
Initially, it was assumed that the site would be without a personal account. Users will go to the site, select the desired section, buy video courses, pay for them, and a link to the course (video on YouTube) will be sent to the specified email address. Also, the task was to make operations on the site simple and understandable, so that the owner (a person without knowledge of programming languages) could manage it, independently add sections and products, send out mailings and edit information. The programmer advised to use Opencart as the most optimal for these needs.
Unfortunately, it was a bitter experience of cooperation and I was left, so to speak, with no idea what.
When paying for the course, the link is not sent to the specified address, nothing happens at all. The payment status does not change. That is, the amount for the course is transferred according to the details, but no response is received.
I turned to a freelance programmer for advice, he said that there are only two options:
1. Place orders manually and create a personal account, that is, each order will need to be supplemented with information so that the link comes to the buyer. And he will be able to see this link only in his personal account. (all this is terribly inconvenient)
2. Build everything anew. (I understand that it is more profitable to build everything anew, and not to delve into someone else's work)
Actually, I want to ask experts where I made a mistake, what did I do wrong?
Maybe initially I chose the wrong CMS or there is some other reason. And how to resolve it?
Help guys, please.
Website – englishwithirina.ru

Answer 1

And what about cooperation?
Your problem is that you made a site that doesn't work and, being unqualified, you were unable to diagnose and fix a specific technical problem.
Why do you make entire websites at all if you are only a designer?!
Obviously, now the designer needs to either improve as a programmer, that is, learn OpenCart and PHP and solve the problem, or find a specialist and share the money.
He told you something wrong, which personal account, why redo it.
To this or not to that is another question, this problem could happen with any CMS, and also with any CMS it is solvable, not a single normal CMS blocks the use of PHP directly, and everything is certainly possible on it, as well as any normal CMS can be at least edit, that is, redo something that does not correspond to the task, and usually the CMS also has extensibility, that is, the regular ability to change something without "getting" into the code of the CMS itself.

Answer 2

Do everything simply on html, link the order form to a php file through it, make a payment to an aggregator or a bank, to edit textolite content.
The simplest option would be to choose the right system initially with all the functionality

Answer 3

With the placement of the video is not very well thought out. Anyone who has bought a video and received a link can forward this link to anyone or simply put it in the public domain, which will happen sooner or later.