Any chance you bought it on credit? If you want to really get their attention, you can always initiate a partial charge-back for quality of goods not as expected (do it for the amount of repairs, not the total price)...change-backs are WAY expensive for businesses to deal with, and if they have too many their merchant services company can actually cancel their contract...
Even Performance Bike has dealt with problems more minor than this with more respect...I'd be pissed as you-know-where if I were you...