You are slow just stop responding. Opening the xbox to mod it is your right to do so. If it breaks or gets banned from xbox live it is not your right to return it for a full refund. Either fix it yourself with x-clamp and keep it out the case or buy a new one.
I am speaking from experience here my first 360 I did the x-clamp because my warranty expired. It worked fine for 2 years out of the case then it finally stopped turning on. I wasn't a dick and try to return it I bought a new 360. Guess what that one got banned from xbox live. I didn't return that one either I bought a 3rd xbox. This is how a normal consumer should act.