We got two of these for our boys, and a couple weeks into using a rear derailer broke on one of them (derailer is made of plastic). Brought it back to the store to have it repaired and was told it should be 2 weeks to get it back. It's been more than 2 weeks now and they are unable to tell how much longer it should take. The kid is upset as he can't enjoy the time with his friends before school starts...