Complain about service plan on my Hyuandai vehicle.

I bought my car in 2018 in Randburg JHB by a sales person Johan. I have been fighting with hyundai to complete my service plans. I was told my service plan would cover me up to 60000 km, and I am currently still way at 59615. I have now booked my car for a service at hyundai Brakenfell, where I was told they could only assist me with a 59000 km. I advised them of my mileage on my car and was told to contact ***, with my I.d no. and vin no. I contacted them and I was told that my service plan would only assist me with in 45000 km which means I was mislead by the sales man Johan. They advised me to contact the dealer which I did, and he suddenly can no longer remember the deal/agreement. Johan no longer works at Hyundai and advised me to contact Corinae on *** at the dealer where I bought the car. I called three times yesterday and left a messages. I called today again and left more messages. I'm very very disappointed with hyundai, and my friend is experiencing the same issue with Hyundai. I do not have the funds to forfeit the cost for this service to be done as I was misinformed about the plan I was on. I insist that this issue gets addressed and brought to someone in management's attention. If I am not contacted with in two working days, I assure you that I will take this matter to social media and address my lawyers to take further action, and I assure you I will hold huyandai liable for the legal cost. This kind of professionalism in a huge company such as Hyundai will not be tolerated and I, the client have my right to addressing issues which you do not stick to your word.