What Russian-language chatbot platform for developing an expert system (quizzes, questionnaires, not funnels) would you recommend?

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I plan to use the chat bot(s) as an expert system that allows the client to solve his problems by passing the quiz. Each quiz is a complex branching structure with a different, unpredictable number of steps for each client. The service will be inexpensive and distributed by subscription (monthly payments).
Please help with the choice of a chatbot platform for the implementation of this project. Based on the above requirements, the following:
1. The subscription fee for using the platform does not depend on the number of messages sent to the chat.
2. A single interface for building quizzes (funnels) for all major messengers. The expert system will be constantly improved. You need to easily adjust certain steps and branches of the quiz at the same time for all messengers. Ideally, the client can switch from messenger to messenger on the fly, while in the quiz.
3. Ability to store a large amount of customer data in variables and/or through simple integration with external storage (eg Google Spreadsheets). Preferably without violating the law on personal data.
4. Possibility of payment by the client for services directly from the chatbot. Possibility of automatic debiting of subscription fee.
5. Sane support, extensive help system, free lessons.
6. Guarantee of long-term work in Russia.
7. Free tariff and/or testing system.

I look towards SmartSender, but for some reason this platform is not even mentioned, for example, in Townsend. There are negative reviews about support, complaints about debiting funds, there is no certainty that the platform will continue to work in Russia (at the moment I only load via VPN, I have not checked the passage of payments yet).