Casino withholding 25% since I'm Canadian

[T_Mac]

I hope this is the right forum to post this in. I won a tournament at the Rio and they withheld 25% of my win because I'm Canadian. I approached a company called Refund Management Services about getting my money back, and found out that RMS charges a 25% fee as well. Can someone tell me how easy it would be to get this refund myself? Or should I just bite the bullet and use RMS.