I am 6' 3" 305lbs. and am new to cycling. I am doing it for excercise but have found it very enjoyable and addictive. I am just riding on the road. I purchased a Diamondback Edgewood from Dicks because it is supposed to be rated at 500lbs and it broke so they gave me a new one. I am already having problems with it clicking and the chain popping off. Should I take it back and demand a refund or is this a good beginner bike?