I don't know how that bike got you around the block. LOL Bike companies are getting dumber every year. Sad thing is, these bikes are selling like icecream in Florida.
Defailleurs just don't like weight. The only bikes built for weight are expedition tour bikes with a Rohloff14 and Dutch 3 speeds.

There's been 3 similar threads lately for broken spokes and wheels.
On Snapping Spokes