Problem when post a service credit memo

Hi All,

When we post a service credit memo , we a have an issue related to customer balance . the original amount in Service credit memo is 6000, What is posted is 6000 in general account but 400 in Customer ledger entries.

Detailed Cust. Ledg. Entries
Posting Date Document Type Document No. Customer No. Debit Amount Credit Amount
02/06/2014 Invoice NFS-14-14558 CL-00011335-CRM 400,00 0,00
01/07/2014 Credit Memo AVSE-0150 CL-00011335-CRM 0,00 6 000,00
01/07/2014 Credit Memo AVSE-0150 CL-00011335-CRM 0,00 400,00
01/07/2014 Credit Memo AVSE-0150 CL-00011335-CRM 400,00 0,00