Can anything be done about this? I need help from someone who knows this world better.
Jetwin have a review page in
AskGamblers you should post your case there as well, i'm not sure if it's going to change the situation but it's worth a try as they usually act on the posted issues.
where can I find a casino that wont screw me over if I do win something and wont restrict me because I am an american ?

The only casino I know that accepts gamblers from the USA is Nitrogensports they only have a few games but you'll probably have a better experience over there.