I am trying to get the monthly credits earned by our plus customers (Customers who opted for a subscription). If a customer paid in that month, then his credits should be included and if the customer decided not to pay in that month, credits should not be included. I am not sure how to accomplish this in Amplitude. If I make a condition to check if a customer paid any one of the months, I get the credits of all the months and not the months when he actually paid.