Terrible after care service from NTT Volkswagen Worcester

My mom bought a new VW Vivo at NTT Volkswagen Worcester 6 months ago. She realised after a month that she did not receive a spare key and when contacting the branch she was told that the sales person left and went to work at another dealership. She spoke to several people who promised that they will follow up and get the key to her. My brother finally send a mail and was told that they spoke to the person who sold her the car and he said that he checked and there was definitely a spare in the car manual. However, we went though the car manual several times as well as the car, but there is no spare key. Their only response is that according to the sales person the key was there, so now it's the sales person's word against my mom's. This is so frustrating as my mom is an honest person and have no reason to lie and say there was no key. What happened to good customer service and making sure that the after care service is as good as the making the sale?

My mom would now be forced to buy a key for R1800 and although it's not a lot of money, it's not fair and NTT Volkswagen Worcester should choose to do the right thing and give my mom the spare key.