If you don't trust the place you bought it. Then take it to any shop that is a authorized Trek dealer or service. Your PSA is a little lacking in any detail of why your incident will also be had by everyone that owns and rides a Trek Marlin.
You'll do more good for other Marlin owners if you go to a bike shop with this to get Trek some information about what happened. And you have to accept the fact that your incident might not actually be a thing for everyone.
If you don't want to seem like a unhappy person that just rants and flames on the internet, then you need to provide more details and calm reasoned thoughts.