Invalid key

[Grouch-O843]

So I'm new obviously and I've been putting some time in and want to get in a race lobby and every time I hit race it pops up invalid key.... I registered my key after my purchase and i purchased off of the Mxb website not steam I've sent two emails to the mxb support email I got off the forms looking into the issue before I reached out with me name email and my key I was given when I purchased it has been over a week and I've gotten no response from support what should I do is there anything I can do? Please help thanks in advance