Hi Srinu,
1. First check the documents which are not reversed. There might be cleared with some other document or itself a clearing document. For that you have to reset the document by FBRA.
2. For sale posting, check whether it has created through SD. If it is, then you have to cancel the billing documents by VF11.
3. Check COGS posting, if it was posted through VL01N. You can cancel these document by VL09.
Regards,
Mukthar