I agree that changing the rules without warning was a bit unfair. However you should realize he unwillingly did you a favor: you lost 3k with 80 max bet, with 320 you would have bet 4x, with the same exact pattern most likely, and would have lost 3x4=12k.
Lowering the max bet only had the effect of slowing down your gains, so you felt like going on for much longer, eventually losing.
You said if he lose and at the other side what if he could win ?
(Nothing personal)