The seller's name is on the UPS paperwork, that means he is responsible for handling the claim. Which means that any money refunded will go to him.
As a buyer, what happens between him and UPS is not your business. The seller did not send you the T1500 before you paid for it, you should not have released the T1500 back to UPS until you had your money returned. That's the way the system is designed to work.
Fussing with UPS and the insurance is not your problem, it is the seller's problem. I have dealt with this from both sides, the seller is screwing you, not UPS.
As a buyer, what happens between him and UPS is not your business. The seller did not send you the T1500 before you paid for it, you should not have released the T1500 back to UPS until you had your money returned. That's the way the system is designed to work.
Fussing with UPS and the insurance is not your problem, it is the seller's problem. I have dealt with this from both sides, the seller is screwing you, not UPS.