Ruined brake system!!

I took my car to Supa Quick Cresta branch a month ago because it had started taking too long to stop when braking. They checked the car & said everything looks fine but they decided to skim my discs… all of a sudden when I left the branch my car started making a grinding noise when braking. I went back to them 2 days later & they told me they’re about to knock off (I got there at 16:15 on a Monday) & their employees don’t get paid overtime so they can’t help me, I must just keep driving the car & the sound will hopefully go away. I am ****ed off coz it’s been 4 weeks & the sound is STILL happening… the sound was NEVER there before I took the car to them!!! Wasted my money & they were not willing to assist/fix their ****py work!!!