GlobalTestMarket playing games?

Now, I don't know if they are doing this on purpose or not, but I have been pursuing GlobalTestMarket for my check (for doing surveys) for over 6 months now. Each time I get a reply from the customer care rep that they sent the check to me, but my address was "non-deliverable". Now, that's a real joke because, first of all, my address is definitely not non-deliverable. Secondly, someone is always home to receive the couriers/mail. And thirdly, for God's sake, they have already sent me a check on this same address before. Now they say that they are sending out my check for the third time and, if this time my address is again non-deliverable, they are going to forfeit my earnings. Sounds fishy, right?