The forum issues may have driven you away in disgust, but just in case you do return, tell us what rims you've been buying. I don't know the Coleman (Chinese made) karts too well but know the GK200 is a "kiddie kart" with limitations. If you've been buying OEM replacement rims, then perhaps you are not improving the situation. It's a smaller kart and that means lightly made, light duty and for light passengers that do not stress the wheels and frame. I've seen adults riding these though, because they turn almost within their own length and are light and fast.
A GK200:
Don't be surprised that replacement parts are often worthless junk. 99% are made in China so they are, indeed, junk and not meant to last for long.
When they got bent, did you try unbending them?
I once drove a car with stock "steelies" and hit a softball sized rock in the middle of the road at 65mph, don't ask me how. Pulled over, saw the wheel had a huge U shaped dent in the rim and it was losing air. Afterwards took it to a tire shop and the dude there bent the rim back down into shape with a large lever tool. Put 35psi in it, good as new, only took a minute.
Post some pics of the damage. It could be due a factory defect. . . . . . . . . .