Administration of customer credits/deposits
we are looking for a possibility how we could handle following request in SAP:
A customer has a credit/deposit of 6000,00 EUR (was part of machine sale, can be used for training or parts).
If the customer applies for a training then the costs of 3000,00 EUR should not be charged(invoiced), the costs should be cleared/charged against the deposit. So the customer will not receive an invoice, but the deposit is only 3000,00 EUR now.
If the customer applies for another training and the costs will be 3500,00 EUR this time, then 3000,00 EUR should be taken from the deposit and the customer should receive an invoice for the remaining 500,00 EUR.
Is there any way how we can handle this in SAP? We are currently using Excel for the administration and everything is done manually.
Could you please give me a hint? Thank you!