Which VOIP provider to choose for cold calls?

Question

Telephony

Good afternoon.
Colleagues can you recommend a VOIP provider for outgoing line (cold calls)?
The essence of the problem is as follows: you need to make a lot of outgoing calls. When a certain limit is exceeded, we are constantly blocked for fraud.
I tried to buy numbers for free - it is blocked on the next business day.
I tried to insert SIM cards into the GOIP gateway (With IMEI substitution) - each SIM card is blocked after 5 days.
The main problem is the shutdown. We need some more stable solution.
Can anyone give some advice? How do spammers work? How do mobile operators detect fraud (actual criteria are needed, for example, if it has exceeded 10,000 minutes, etc.)?

Answer 1

1 - who have you tried (operator), who is blocking you?
2 - what is your traffic volume (how many calls per day do you make)?
3 - average talk time (10-15 seconds, or 2-5 minutes...)?
4 - do you have live operators who communicate with the called person (lead) by voice? Or do you automatically (robot) pronounce some text?
5 - where do you get the bases you call?
6 - what caller ID are you setting? Are you ready to answer the calls of people who will call you back? Or if you call your number, you hang up? Or is the number not responding at all?
By answering these questions, I will answer all yours. Otherwise, there is very little information.

Answer 2

1. It blocks for nothing for ASR < 20% (We have ASR in the region of 15-18%) .
   The operator whose customers we call (TELE2) blocks us by CallerID (AON) approximately 2-3 days after the start of using the number, something like a black list, but at the level of the telecom operator (subjective sensations).
   We tried beeline sim cards in the GOIP gateway - here it already started blocking beeline, with the wording "for fraud".
   
2. 30 thousand minutes/month
   
3. Average talk time 127 sec.
   
4. Live operators, call and offer services.
   
5. Gives the customer, where he takes it, we do not know. But he obviously says that no more than 20% of the numbers from the database are alive.
   
6. Well, the AON that the provider gives us, Zadarma gives a number in the ABC 499 code, in the case when we use beeline - DEF beeline number. When people call back they are answered by a live person.