I accidently transferred ETH (was default even under ErC20 token menu option) in my Trezor wallet in stead of selecting LINK and then I transferred it to my own Luno LINK wallet address. The ETH naturally never arrived in my Luno LINK wallet, even though there was more than 7000 confirmations/validations that the transaction was delivered successfully.
Is there any way that I can transfer the ETH back into my Trezor ETH wallet?
Contact their support, please. Nothing can be done about confirmed transactions out of Trezor.
Since it never arrived in the Luno wallet, Luno say they cannot help
we cannot either, unfortunately. Confirmed transactions are not reversible, if you sent it incorrectly.