Copy trading

Hey, 

I have a MT5 account with an EA who work 24/24 for my money. 

I have some people who can pay me all month to copy all of my trades. 

BUT, I want to make a system with 30 day trial and after a 30 USD/month. 

To make this thing, I need to have an access to the data of people to stop there signal after 30 month if they don't pay. 

How can we make it ? If u have an idea, tell me. 

(I would like that the copy system is independent of the mql5 signals)

Thanks.