Credit memo

Hi Experts,

I have a problem, Company code A sold some material to Customer X for an amount of Rs.4000/-. The customer X returned the material to the Comapny code A due to some reasons. Comp code A gave a credit memo for Rs.4000 to X. That credit memo was not utilised by customer.

In some other transactions, same customer X has to pay Rs.700/- to same company code A.

For more than 4/5 years, there were no transactions between this company code and cutomer. But Company code A send a mail to customer X to pay the amount Rs.700/-.

But the customer rejected this and told that A has to give me 4000 and deduct the amount 700 and pay me back the remaining Rs.3300/-.

After verification A found that it has to pay 4000/- to X.

Could some one give me some resolution how to process this in SAP smoothly ?

Regards

Madan