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, the lady who answered told her that they are still busy with it and will let her know when it is ready. By 15:30/16:00 there was no communication still and since she was worried about closing time and traffic she contacted me to Uber her there. She then got stuck in traffic and it was also raining so at 17:00 whilst on her way she tried to call again and it was direct to the answering machine, she was now panicking that they would lock her car in and knock off without letting her know.

When she got there her car was just sitting on the side, no-one paying any attention to it. She then discovered that her car was not serviced that day because it had been serviced in June already; this is something that was clearly found out earlier in the day 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 the person who answered the phone at 14:00 actually 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 at least they always communicated; this one was the worst of them all. So disappointing for such a big and loved brand.