A very common practice in the world of billing is to set up and operate customer in a Prepaid manner, meaning customer accounts can only use services to a value not exceeding the deposit held. This ensures that your accounts receivables is always in the black and your customer is never owing you.
To operate a customer account in a Prepaid manner please follow the steps below:
Go to the Invoice Items module and create an new Invoice Item called "Prepaid Credits" with a negative Unit Cost as follows:
Once saved your Invoice Item should look as follows:
Create a new Recorded Invoice for the customer account that you would like to operate as a Prepaid account and add the Prepaid Credits Invoice Item to the Invoice.
NOTE
Increase the item quantity to the desired amount so that you have the line total that you want. Here we have the unit cost of the Prepaid Credits Invoice Item set as $100, so if you would like your customer account to have $600 of Pre