refuse to service my car

VW Midrand refused to service my car. i have a service plan on which this was supposed to be my last service they said they couldn't do it because i'm over 60000km's by 3000km's and so they saying i forfeit my last service.i booked in my car as soon as the service sign went on meaning at the last service it must have been set to go on by the next 15000 km's.this was not communicated to me that i have to bring in the car at exactly 60000 km's all i know is if a car is due for service it'll notify you and it did. my dispute is why must i forfeit my last service i mean i paid for the service plan it was not given to me for free. my understanding is if you pay for service it must be delivered...i found their service really bad cause when i booked in i gave the consultant my mileage but they left me to drive all the way to them and leave my car for them to call me at work and tell me all this.i calld VWSA no one answered i was on hold for 1hr and sent them email even commented on facebook page no one responded i'm shocked to say the least to think i have 3 cars all from them...this really disappointing!!