Sounds like a pretty bad bike shop. You were looking for a city bike/commuter, and the shop sold you a mountain bike. None of us were there, so hard to say who is in the right and who is in the wrong. (did you emphasize you primarily needed this as a commuter?) Take it back and at least see if they will swap out more appropriate tires, maybe adjust the fit. Or take it to another bike shop and pay them to do what you already paid the first bike shop to do.