21 Prive Casino - Unfairly confiscated winnings due to unjustified accusations of max bet breach

hello-
on 20/11/16 i deposited for the first time with 21 prive and took the 200% +100 free spins welcome offer, after meeting all the wagering requirements to which i was emailed by 21 prive congratulating me on doing so i made a with drawl of 750GBP on the 21/11/16, on the 24/11/16 i opened my account and saw 20GBP in my balance and assumed it was money left over from the day before as i had played daily since depositing, before signing out i looked at my pending with drawls and found that there were none so went on to live chat were i was told an email had been sent that would explain, the email they had sent read - as per clause 7 (vi) of our promotion terms and conditions the max bet allowed while the bonus is in play is 5GBP should you bet higher than this the casino reserves the right to confiscate all winnings, your with drawl has now been reversed and your account has been adjusted accordingly, i replied to the email and asked if they could please show me were i had bet higher than the bonus terms as i had been right through my history twice and nowhere had i bet higher or even as high as 5GBP, they emailed me back a couple of days later and it read - the decision made by our accounts team is final, there was no explanation as to why or as asked to be alerted to the alleged bet or bets- nor when thinking about it had they claimed that i had bet higher than the bonus allows they had just quoted the clause 7 (vi) jargon at me and took the money!, i can only conclude that 21 prive deems the amount i won (FAIRLY) was to much to pay out so took it back, as i said to them in my follow up email - what they have done is disgusting and that it was not the end of the matter by any means and i REFUSE TO BE RIPPED OFF.
Having being informed by 21 prive that the decision is final and therefore communication is over i would be most grateful if you could please assist me in resolving this matter.
Please feel free to contact me at my email address - < email removed > should you require any further information.

best regards - william < surname removed >