What online CRM systems exist with helpdesk functionality?

Question

Android

Good afternoon.
Advise CRM from the existing, cloud-based type with the following functionality:
1. Conducting transactions in the service sector (registration of new customers, automatic and manual creation of transactions based on filling out forms and sending letters on the process of providing services (i.e. point 1 is passed, the client automatically a letter was sent about the second point)
2. Possibility of integration with telephony (preferably based on Android devices)
3. Integration with mail, social networks, chat from the site directly in the system (helpdesk)
4. Financial accounting (ideally with the possibility of invoicing and control payment)

Answer 1

megaplan.ru - I use it myself

Answer 2

Agree with previous comment. Better get a mix. I will answer on point 3. Chat integration on the site with CRM. Here is the solution - NETROX SC which has CRM integration documentation.
Documentation
There are ready-made templates for amoCRM, Bitrix24 and Megaplan. In general, the engine is universal.
Description