There are not many options:
- you used a fake resource to transfer funds
- your seed phrase contains an error or a mistake, because the mechanism of the seed phrase, and the algorithm for working with it is deterministic, which means that only if the seed key matches 100% will you gain access to your wallet, and if the difference is 1 bit, you will not get access to your wallet. This is math, and here "a little mistake" gives a guaranteed different result
Isnt strange if mistake happen? Since after create the wallet, theres a check to verify that the seed u save is correct 100%, Possibility is only he send to wrong address or maybe the metamask that he download is a fake one.