Sometimes sports bet predictions are leaked and with proper source you will get to know who's going to win. Maybe they found you suspicious as you are always winning on sports so they limited your sports bets. However your bets are fair and it does not involve any cheating but the information may come from outside. Maybe they are not sure why you are always winning on sports so they just put your sports bets on the limit.
The best you can do is wd all your money from their and try another trusted site.
You do not necessarily have to do something like that, as that would be considered to be a form of cheating, there are people out there which are so good at sport betting that they can in fact beat the casino at their own game, but if you do this consistently then it is obvious that casinos are not going to be happy about this and they will limit your account, so as you have said the only solution for the OP is to to open an account at another trusted casino and move on.
Gambling or betting platforms are businesses which they would really be eyeing into those bettors who do constantly win or does have high winning chances or statistics which we know that it wont really be that
good for the business which it would really be just common sense that they would be limiting out you withdrawal or winning or something in related just for you not to have that full extent
on what you are tending to bet.
There are lots of platforms which we could choose from if ever we've been limited out by the current platform that we are using.
Cant really deny that there are people or gamblers who are really good at betting specially on sports.