Bad service and don't care attitudes

On 9 December my mom took her car in for service. She is 65 years old. By 14:00 no-one had called her to advise on how far the car is and so she gave them a call, it was answered by NAME who told her that they are still busy with it and will let her know when it is ready. By 15:00/15:30 there was no communication still and since she was worried about closing time and traffic she contacted me to Uber her there. When she got there her car was just sitting on the side, no-one paying any attention to it only to find out that she had serviced it in June which is something that was clearly found out hence the lack of attention. Question is why didnt anyone look at the service book before taking the car in? Once it was discovered that it was serviced already, why didn't anyone contact my mom to pick it up? Why did NAME not do a thorough check up on the car and give the correct feedback? A day was wasted for nothing. No empathy has been shown to my mother. No customer service whatsoever. She doesn't usually get the best service from them but this one knocked all of them out the park. So disappointing for such a big and loved brand.