pearsorp

I just recently replaced my unlimited slip differential, ring and pinion with all the new bearings and seals. I had a shop put the stuff in. Not even 500 miles into the new differential and it started whining. I took the truck back in and they pulled everything apart and I seen some small metal shaving. very small!!! So I called the place that I got the parts from and sent them pictures and the guy from west coat differentials tells me the shop had the backlash to tight. So does this mean I have to replace everything again? Maybe just the bearings, ring and pinion? This company is having issues with my repair because I live over seas and there is a communication gap. I gave them the instructions and I'm thinking they didn't follow them. Any help is needed. I can email pictures if needed.