contango 

I don't know the law in your area but if they sold you a bike that clearly wouldn't take your weight (and assuming you were open about your weight, so they couldn't hide behind fluffy excuses like "I didn't realise the rider was so heavy" and "S/he carries the weight so well I had no idea" and "I didn't want to tell the customer they were fat") then they have sold something that clearly isn't fit for purpose.

Depending on your local laws that might be something you're supposed to know even if the salesman tells an outright lie, it might be something that the shop has a high degree of responsibility to get right even if you get everything wrong.

At the very least I'd hope they would give you the full value of the unsuitable wheels towards a new set, although if it were a legally valid option I'd be looking to give them the whole bike back for a full refund (not a partial refund) so I could buy something better elsewhere. You already know the rims won't take your weight and from what you've described of the popping sound it's possible something else has failed as well.

If the bike shop isn't interested talk to Trek directly. I'd hope they would be interested to know if their name is being discredited by one of their dealers selling bikes that aren't suitable for the rider.