Ebay Feedback Question

I hope this is the right place for this. I bought a small lot of Indian Head Pennies a couple weeks ago on ebay, and what I received was less than pleasing. 90% of the coins were badly damaged, bent, run over, and what looks like chisel marks on some, along with severe verdigris on many. there were 27 coins and maybe 6 are ok. I messaged the seller and he refunded half my winning bid, and was happy to do it. He asked me what I thought was fair and I agreed to half, but haven't left any feedback yet. Hindsight being 20/20 I now think I should have gotten a full refund. I am not satisfied with the purchase after partial refund now that I've thought about it. Too little to late? My opinion is this: I would not have sold the damaged or corroded coins without disclosing their possible condition to the buyers taking into mind this was a "random" lot taken from a larger amount of pennies. There were no pictures of the actual said coins in the auction. I know I could have done better on my part as a buyer and be aware that I may receive coins in less than desirable shape. I take the blame for that. But still I feel these coins were not worthy of selling in my opinion. What should I do?

1. Discuss with the seller another resolution.
2. Leave negative feedback despite his willingness to resolve the issue.
3. Do nothing and chalk it up to experience.

I'd really appreciate any input on the issue.