Hyundai services are unaffordable and their service is pathetic!!!

I purchased my Hyundai i10 from the Glen in December 2017. I was given a 7 year warranty provided I service my car at a Hyundai service center or any RMI approved workshop as informed by the sales person. My car is due for service now and i only recently found out that I can only service it at a Hyundai service Centre and if I get it serviced any where else even if it is a RMI approved my warranty would fall off. I budgeted around R2000 for the service as that is what I was told by the sales person it would cost but when I called Hyundai last week the quoted me R2600 I then tried to buy a service plan which worked out to much more and when I queried as to why it would cost that much I did not get back a response. I called Hyundai today again to book my car for a service and when I asked the lady how much it would cost she now mentioned that it would cost R2950. I cannot understand why this amount keeps on changing, she then said I must come in and they will check again which means Hyundai cannot give you an accurate quote telephonically but they expect you to book your car in without knowing how much you would be charged. I think that their service is pathetic and I am considering selling this car because I cannot afford to maintain it! A very unhappy customer!!!