02 Silverado Brake Problem

I'm having a problem with my brakes on my '02 Silverado. When I would hit the brakes, it felt like my ABS was kicking on, but my brakes weren't working - at all. THe truck wouldn't slow down at all, and then the brakes would seem to catch and usually stop me inthe nick of time. I found out there was a recall on the wheel sensors, so I took my truck into the dealership today. They told me that they fixed the recall, but it still was having the same problem because one of my wheel hubs was an aftermarket part and it wasn't compatible with the GM one. Sounds to me like their feeding me a bunch of BS. I know people that have had the recall done on Chevy vehicles and htey had an aftermarket hub and it worked fine. Any ideas as to what my problem could be? I'm not paying a dealership $500 to put a GM hub in place of a perfectly fine aftermarket hub.

Is it possible that buying an aftermarket hub for the side that works would make the problem go away? Then I would have 2 aftermarket hubs on (although why and aftermarket and a stock hub would be compatible doesnt make sense to me). I'm just looking for a cheaper fix then buying a new stock hub.