Need help – merchant disputing transaction took place

I sent an eth payment last month to a merchant's coinbase account, and theyre telling me that they never received it, even though etherscan says it completed, and the eth is missing from my account.

Do i have any recourse? I have evidence that the wallet address is correct and belongs to them.

EDIT:

I’ll update with the clarification here –

I bought an item from the merchant who was using Coinbase. Unfortunately I used a low gas fee and it didn’t go through immediately. Actually it didn’t go through for a month since it was only a 70Gwei txn.

In the meantime I paid the merchant in PayPal expecting that the txn would never go through since it was such a low gas fee. Well…it went through a month later on 4/10/21 and I essentially paid twice.

I contacted them on 4/14 and said that I wanted a refund (the sales associate already assured me that they would refund the eth if it ever posted). Now they’re telling me it never posted even though I sent them the etherscan. I even have proof I used the right wallet address (which matches in the etherscan).