Sarkis, you said that you dropped the DVDs in the drop box. Most of the public libraries have a policies that don't allow DVDs, video cassettes and CDs to be dropped in the drop box (which is for books only). That may be the reason they forgot to check the DVDs in.

They may have already shelved the DVDs and forgot to check them in. You can claim the DVDs as turned in and they will try to find the DVDs. A couple of years ago, they forgot to check in some of the CDs that I had returned. When the CDs still appeared on my account, I went to the libary and searched in the shelves. Then I told them that the CDs were already in. They then took the CDs out of my account. So, the best option for you would be to go to the library and claim that you had already returned the DVDs.