Usually it's hard for me to believe stories like this but if you really did a KYC then I think I can believe you because why would you do that if you know that you are guilty of abusing the site? You just put yourself on trouble because they will know your name and address, and they can send a police at your doorstep.
Op can be telling the truth that he didn't use multiple accounts. But being able to kyc shouldn't be a justification that OP is innocent. Even if Op cheated and won $3.6k, he would try his luck anyways since it's now a dilemma. You shouldn't expect him to fizzle out easily because he cheated.
Anyways, I believe must have launched a complain on the Ann thread of Sportsbet as advised by many. We shall know the truth though.
It is important to read T&C of any site before depositing money. This is because they won't stop you from putting in money, but they can stop you from withdrawing .