Brake Grinding Noise problems of the 1998 Dodge Durango

I bought this car used in the last week of November '08. I had my brakes done by an individual maybe two weeks later. A couple of day later driving home from work I started hearing a real loud iron grinding noise. The next day I had the car towed to aamco, who told me my caliper pins had came out, and I would need a new steering knuckle and a set of caliper pins. The truck was fixed costing me $525 (noting: mechanic used a used steering knuckle. ) now 2 months after those repairs I need a wheel spindle, and caliper bolts because the threading have stripped away and something totally unrelated a neutral safety switch. Costing me $580. I was told that by firestone who told me I needed new tie rods and then corrected themselves by telling me I needed a new steering knuckle - who wouldn't even work on my car because of liability told me that it was unsafe to drive because the right front tire could literally fall off due to lack of support and cause a major or serious accident, and that I needed to take it back to aamco. I didn't want to because I felt aamco should have fixed this the first time. But after fighting with them and reading the other complaints maybe they're not in the wrong.