My gazelle ultimate t10 plus just broke, need some help finding the correct part

My gazelle ultimate t10 plus broke, specially the crankset is bent and the chain flew off. What is the part that it uses? And is there a "better" quality part that will work the same if not better.

I had it looked at by sun and sky sports a week ago, they fixed a separate issue now this happened. Evey few weeks something goes wrong with my gears and chain, was this a cause of the those random issues?

(The bike has a total of 720 miles put onto it all by myself, very light off roading, but heavy on road, 25 mph average hitting 33)

It kept on switching gears randomly here and there and today it got really hard and broke.

Should I try to fix it myself, or get it looked at? If so what place do you recommend (Austin texas) that won't charge me a arm and a leg.

Or should I sell my bike for how much even I can get from it?