Car ruined terrible job done

My vehicle came back with problems from a service at car service city wynberg cape town. Major service was done and brack disc & pads. Car came back jerking with breaks not holding, took it back i was told they skimmed tgem again & did plugs.

They had told me the skimmed break disc & pads will go as far as 3years Same thing is happening now when holding the breaks a “brrrrr” sound go on and the vehicle shakes taking time to get vehicle stationary.