May I ask which platform that exactly was? Because to be clear: there is no way to transfer ada to an Ethereum address. The wallet software will not allow such an address. If an exchange claims this, then please ask for a transaction id. They will not be able to deliver any.
I know this is still a problem on many exchanges and they will likely charge you for “investigation costs” or “recovery costs” but protocol wise you can not send ada to an invalid (in terms of Cardano protocol) address.
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