Received 10 Payment - What is the meaning of that?

I am assuming you're referring to the payment submissions, you can get it if someone submitted to your Order forms or forms with payment integration. Here's the difference between normal submissions and payment submissions:

Submissions Received (monthly): This is the number of submissions you can receive on a monthly basis. The count covers the calendar date which means 1st day to last day of the month.

Payment Submissions (monthly): This is the number of submissions that have payment integrations on them. You can check this guide on how to create a payment/order form. So for example, we have Paypal payment integration on our form, if a user fills out the form, submitted it and successfully completed the payment, then that would be counted as a payment submission. 

Related guide: Understanding-Your-Account-Usage-and-Limits