You should check what blockchain did you hold your IOTX tokens: IOTX is a native token of the IoTeX Blockchain, but it’s also available on other chains in the form of an ERC20 token.
In general, if you see your transaction information on iotexscan.io then your tokens are on the IoTeX blockchain, if you see the transaction data on etherscan then your tokes are on Ethereum.
If your tokens are on IoTeX then just import the private key of the recipient address where you sent to tokens in the ioPay wallet. If they are on Ethereum instead, then just import the private key of the recipient wallet in Metamask and make sure your Metamask network is on “Ethereum”