Damaged only just discovered

I bought a dvd box set as a Christmas present for someone.

The case had some damage, but they didn't mind, so we kept it.

We just got to season 5 and discovered a damaged disc. Didn't check every single disc at the time as getting them off the case is awkward.

It's now nearly 7 month since purchase. I tried contacting the seller - no response. I tried to get Ebay on the phone - it's getting harder to get through the bot questions to a person.

Anything I can do? Or is it just too late?