River Belle Casino - Unreasonable verification process followed by unjustified confiscation of winnings and account closure

I deposited SEK 2000 and received a bonus. Once the money was lost, I received a new bonus offer and deposited another SEK 2000. This money was also lost. The same then occurred again, i.e. new bonus offer and a new deposit of SEK 2000. On this last SEK 2000 deposit, I managed to win some money and after having cleared the wagering requirements, I requested a withdrawal of SEK 16,017. I was then asked by support to provide standard verification documentation in the form of a copy of an identification and a utility bill. I provided the requested documentation, but did not hear anything for almost a week nor was any payout made. I contacted support via chat and was suddenly told that I needed to provide a certified copy of my driver license. Nota bene, the casino did not inform me about this request until I contacted them. The request of such was unheard of from my end and I questioned the actual need for this. I could not interpret this as anything but an attempt to stall the payout. Nonetheless, I went to a law firm/notarius publicus (!) and obtained certified copies (this was not for free...). I sent over the certified copies to the casino.

After not hearing from them for four days, I asked again why the money had not been paid out. The short response I received was that the casino had decided to seize my winnings, repay my deposits and close my account. The casino pointed to this clause in their terms: "5.8.3 In the event that the Casino believes you are abusing or attempting to abuse a bonus or other promotion, displaying irregular betting behavior, or you are likely to benefit through abuse or lack of good faith from a gambling policy adopted by Us, the Casino Group may at its sole discretion, deny, withhold or withdraw from you any bonus or promotion, or rescind any policy either temporarily or permanently, or terminate your access to the Services and/or block your account. In such circumstances, the Casino shall be under no obligation to refund to you any funds that may be in your accounts other than your original deposit amounts."

I asked for the casino to motivate this decision and explain in what way I have violated the terms, but I have still not received a response. Without a satisfying explan­ati­on/­mot­ivation in what exact way I have violated their terms, I insist on the casino owing med SEK 10,017 (SEK 16,017 less the repaid SEK 6,000).