Free Brake check

I had a free brake review on my Hyundai coupe because my brakes were squeeking, I took it into ATS PLYMOUTH who said my back brakes needed replacing (pads/shoes and discs) £450 not a problem except that when i drove out the squeek was still there. I put it down to experience, however recently I had to go to ATS for a free brake check on my Rover 25 this time they said it was the front brakes and i needed new pads and discs as the discs were worn cost £115. I bought some discs and pads from motorworld and had them fitted by a friend, however when driving there was still the rumble occasionally when braking the same as before. I took it to ATS who said that the pads had not been fitted correctly and i needed new discs as the recent new ones were ruined along with the new pads again, but this time because of the damage of not fitting the pads correctly i would have to have the master cylinder checked for damage and a brake fluid change cost £150 od. I am not a mechanic but have a bit of a clue, so i took the car home had it checked by a local garage who said my problem all along was a cracked ABS Reluctor ring. Now replaced problem gone. I am not convinced ATS have a clue and will be avoiding them like the plague in future. Wouldnt mind nobody is perfect but they blamed everybody but themselves and the attitude of the staff stinks. ATS dont seem to be very busy these days I wonder why.