SCAM

Don't contact this schmuck, he'll just try to scam you.  You'll get all the help you need right here in this thread out in the open.

Anyway, if you haven't figure out your issue there are couple of things that could have led to your dilemma, but a little more information will help us help you.

Did you expect an address that starts with 1, 3, or bc1?   Do you remember what software you used to create the mnemonic seed, or was it a hardware wallet?