HELP?

I own a 2013 Passat 2.5L . I bought it in July off a mechanic with all new parts. It has been running absolutely beautiful till about 2 weeks ago. I accelerated up a hill with full pressure on the gas and if I’m going to be honest idk what happened but my car kicked back, I slowed down and my rpm shot up to 4 while accelerating at 20 mph. Pulled over and my front driver side wheel was smoking 😀 took it to the shop and was told I bent the dust collector and told there was nothing wrong with my car. But now when I start the car. I can’t reverse unless apply full pressure and releasing on the break. And if I’m driving on the highway or at high speeds, it’ll randomly kickback and rpm will shoot up like it’s trying to accelerate but can’t. And the only way I get this to “fix” is by pulling over and applying pressure and releasing on the break. Is this something with my transmission? Should I check transmission fluids etc or just bring it to the shop immediately. THANKS IN ADVANCE