Annoying for those involved, but something like this can happen. The main thing is that the record player is the one you sold and is in good working order. I once sold an X-Box that I hardly use with a lot of games. The price was ridiculous, so I didn’t give it away. I delivered the device and asked the woman to connect it for her children so that she could see that it worked. I rarely used the X Box and tried it again before selling it. The woman said I didn’t need to connect the X Box and her husband would do it when he got home. As soon as I got home the man called me and said the X Box was defective. I told him that I had tested these before and offered his wife to install them on site and try them out. Since she refused, I assume that as happy as the children were, their own X Box had apparently broken beforehand and he wanted to get another one for free. I didn’t hear anything more after that. I think they wanted to deceive me. For once I wasn’t being fooled. 
Since then, I have been taking photos of the serial numbers or noticeable features, such as light scratches, so that I can recognize my items. I recently heard that you need an expensive spare part for your car. Simply rent a rental car, convert it and return it broken. If you notice it, you won’t get your deposit back. But still cheaper than buying a new gearbox. This is not intended to be a recommendation and I could never reconcile it with my conscience.
Or defective items are sent and later claimed as transport damage so that the insurance company has to pay.
It just shows how resourceful some people are.
Dishonest,cheat and liar seems like more appropriate terminology!
Sorry to hear that you are taking the hit on this. I agree with you that it sounds like buyers remorse. A buyer should be resposible enough to investigate thorourghly by asking questions prior to the purchase. There is absolutely no excuse for the 6 week time delay before reaching out to you!
Good idea.
Hopefully, no issues with it upon receipt. Is the refund conditional on receipt inspection?
So the refund is in two parts. Half was sent already and the second half is conditional upon inspection.
Wish you well.