How can I track conversions from pozvonim.com?

Question

Conversion

In the API settings, there is sending data to Analytics, but when the trial period of the extended version ends, the function stops working. How can I set up conversion registration in a workaround?
Can you get it out of here somehow ?
Widget code example:

<script async type="text/javascript" src="//api.pozvonim.com/widget/callback/v3/bc0642be22052cf391890be6b947019d/connect" id="check-code-pozvonim" charset="UTF-8"></script>

Example site .
There is a description of the API , but I doubt that something will work without payment.
PS. There are several clients, and since only conversions are needed from all the extended functionality, I don’t see the point in loading each one for 6tyr / g.