Zzzz.
Let's dissect this:
1) crank arm falling off, probably wasn't installed correctly to begin with
2) chain broke, not properly installed
3) wheels needed truing, normal for factory built and especially at your weight
4) chain skipping, probably derailleur adjustment, also normal
5) new chain clicking, derailleur adjustment again
You're going to be breaking a lot of things off a stock bike at your weight - other people can enlighten you on what to buy. At 350 you're going to stress any bike you have underneath you.