Service plan.

About two years ago, my sister bought a Kia Picanto and she sent her car in for a service this past week and the service was down but we were NOT informed about the fact that her service plan had finished at 45000km so they did the service on the car and now want us to pay for the service. However, when she bought the car she was told that it was an unlimited service plan for 5 years. We are utterly disgusted that something like this could be done and that even though we were not told that we will have to pay for the service, we are now expected to pay.