Swapzone.IO would have to sort this out if there is any kind of partnership. In this way, they are only there to take their fee from the transactions, and if the user has a problem, it is none of their business. Why does anyone use them at all if they are just an additional intermediary between Changelly and the user.
As we can see, you've sent the funds as a contract transfer instead of an ordinary transfer. Please note that we do not process such transactions, and there is no way for us to credit or refund your coins so far.
Does anyone know what the difference is between contract transfer and ordinary transfer?
and I sent the funds on BASE through Coinbase wallet which is not exactly an obscure wallet.
It's pretty irrelevant which wallet you sent the coins from, in the end, the most important difference is mostly just the interface. Certainly, according to the TX link and the first post, you sent 0.07ETH to some address, that's not in dispute. Here, the error occurred in the communication between user (you) - Swapzone - Changelly.
Usually, many exchanges that stand up to their reputation agree to refund if the address is under their control, but here it is something different.