How can I track orders remotely? Or how to work with a client?

Question

Automation

Hello.
I agreed with the client to organize a flow of orders for him on his Landing page. So far, the conditions have been agreed in such a way that I will receive a fixed amount from the order. But there are a number of points.
1. His goods are sold personally, at a meeting. That is, I can not track whether the order was or not. I can track that there was a request for a callback, but what they agreed on, I cannot know.
2. Are there services that allow you to record all calls from a specific number, and so that you can listen to them online. So that I could keep track of at least meeting arrangements.
3. It's probably easier for him to pay me a fixed amount for a request for a callback and for an incoming call.