Ist sportbet.com sicher?

I made some winning bets and won big on Sportbet. They did mail me a check, but my bank informed me that the check could possibly come back as unpaid weeks or even months after being deposited, and I would be held liable. I kind of brushed that off as my bank being overly cautious. I won big again on Sportbet. This time I requested a payout via Western Union. Sportbet at first approved the request but then informed me that I had been "black-listed" by Western Union, and I could not use that method. I have never used Western Union before in my life, so I knew this was a lie. I even called Western Union, and they said they have no black-list and my name is nowhere in their system. At that point, Sportbet lost all credibility with me. I am currently trying to withdraw all my money via Money Gram, but I am still waiting on approval. I am still worried about the original check coming back as unpaid like my bank warned. Bottom line: I don't trust this site.