The buyer seems right in this case, but what about insurance? Was it offered? Was it declined? That last response, telling a person to check "did not recieve" might be a really bad idea, because I always get delivery confirmation as a seller. You're telling the person to commit fraud. I have to say, as an ebay seller, that person that commits fraud against me, and I have proof of it, is f***ed. Crimes, (it's a crime) which involve the postal service are serious. If someone did this to me I would file claims with paypal, and ebay, and if I'd sent to a confirmed address and could prove it, you wouldn't get your money back. I would also file a claim with the post office, and I'm not sure what would happen but you'd be possibly investigated for mail fraud.
The chargeback method might be worth checking into, but you don't have an umlimited number of these, depending on your credit card plan.
At this point the buyer is asking if they should ask for money back. If I'm the seller, they have a chance to get money back, if they are polite and and it's within my time period. If they write and demand, and threaten, their only hope will be a chargeback. I've been screwed over by buyers and I don't do it anymore. If they are writing about a problem that occurred after my time period to ask for a refund has passed, I'll say I'm sorry, but if I don't put limits on these things then no sale is ever final.
Threatening someone with bad feedback if they don't do what you want is against ebay rules. Paypal will fight more for the buyer, but they are going to read the listing. If insurance was offered and wasn't purchased it is not a "slam dunk".
Here's my advice, and this is what would work if you bought this from me. Write and say something like, "Hello, I was disappointed when I recieved my record as it had been damaged in the mail. It doesn't seem to have been packaged very well. I"m sorry, but do you have another copy of this record so we could exchange?" Showing a picture will help, so they don't think you are a scammer. Read their return policy, and again, it's very important about insurance. If they offered it and you didn't accept, that still doesn't mean that they can ship carelessly, but also, many sellers say that they can not be responsible once the item leaves their hands. Asking for an exchange shows good faith. If he says, sorry, I don't have another copy, then say, okay, I will accept a refund.
If this guy sells a lot of records, he doesn't want a recent feedback sayin g that the record was not packaged well and he would not give a refund. BUT don't threaten bad feedback. It's against ebay rules, and be sure that he is aware of the threat without it being mentioned.
If it was me, and you were nice, and you have good feedback yourself, I would want you as a customer, and I'd give you a refund. If you threatened me, you would never get anything, unless you can get your credit card company involved. What do I have to lose? The most you can do is get your money back, and if you're rude and threatening you're going to have to work for it.
I think I'm going to stop accepting credit card payments, actually, because a lot of buyers abuse that chargeback idea. Many sellers won't take paypal because someone has scammed them as is recommended above. Don't commit fraud over a record. Try it the nice way, and act quickly.