Guess you had better not ever buy anything from Wal-mart, then

Anything that is mass produced is likely to have issues. You got a bad one. If you rule out all CG products from this point on, then YOU are the one missing out--they make some really great products. Sounds like maybe the landing gear wire might have been wrong--a little too big, hence drilling out the wheels and maple blocks, just a guess. They would have made it right if you would have called.

I hate to tell you this, but your friend really didn't pay all that much for the plane--considering it is one of the cheaper ARF .40 sized low-wingers out there.
It's not like you purchased a 400 dollar Christen Eagle and got crap for quality. Realize what you bought. Yes, it should be right, and if you call them, they will make it right, I'd bet my next check on it.

It can be very frustrating not having everything you need to finish a project, especially one like this. However, you could have called them three times now in the amount of time you've vented on here.

If you've balanced it properly, then maybe your motor is just real light. Is the motor all the way out on the mounts? Do you have the spinner and prop on it while balancing, is the fuel tank installed (empty, of course)? These can all make a difference.