Sent USDT to an ETH address via Poly/Matic instead of Ethereum network. Can they access it and return?

Note: This is related to ETH, but involves Polygon, as well.

Yesterday, I used USDT to make an online purchase. I've done it plenty of times with ETH, as I mine via Ethermine and use the funds for gaming microtransactions. This weekend, I took payout into Matic and converted to USDT.

I accidently left Metamask on Matic mainnet instead of Ethereum. I didn't think much about it - just copy/pasted the recipient's address and transaction amount. They responded: The transaction was sent not as a USDT cryptocurrency on the Ethereum blockchain but as a USDT on the Polygon Chain. Unfortunately, this means that we do not have access to these coins, and they are irrevocably lost. It was only $50, but it's still enough to want back, if poossible.

But I just set up my Poly wallet and the leftover Poly USDT is easily visible in my Trust wallet. I believe they should be able to access the coins and at least return them, since I thought the networks were compatible?

I've learned that I need to triple check the network before making transactions - it's not easy, even for someone who has been exposed to crypto for a few years now.