Minimum balance against service.

Minimum balance against service.

Hi,
I am using zoho subscription and zoho Invoice for one of my application. 
In my application, Customers will pay in advance for the services that they may use. Then at the end of the month when an invoice is generated, it should be balanced off with the advance payment that is already done. Also,  Customers should be able to top up the balance. They should always keep a minimum balance of a fixed amount.

How can I achieve this in zoho ?
Can I achieve this just by using invoice and credit-note ?

Any suggestion would be appreciated.

Thanks.