I am not saying I do or don't believe you, but I have noticed that your whole post history is basically scam accusations. I'm curious as to why you only play these small unknown or barely known sites? Seems curious that you aren't gambling on the bigger well known sites and are taking chances on these smaller books.
That's exactly what I wanted to say before reading your post. I always do a research on the accuser's history hee in the forum before passing judgment on the accused person or casino just to ensure fairness between the two sides. Here as you mentioned the OP's gambling activity, is only in sports betting and his the winnings he always makes from betting, does raise suspicions and why these small sportbooks decides to ban him?. However, without a clear evidence, it's impossible to have a conclusion, The accused side is absent and he is offline from the forum, despite their successful contests and campaigns before, that doesn’t absolve them from the accusations.
The reasons provided by the casino for the ban, frankly, they are horseshit and doesn’t make a sense. They didn’t even specify the exact reason of the ban. Given that the OP claims to have only bet on sports, so we take the second reason since the first one can’t be related with sportsbooks.
Your best option now is to file a case with Guru Casino, as suggested by some users before, and hope for a response. If they do respond, the Guru team will reveal the truth behind what happened to you exactly.