Very disappointing/ bad service!!!!!!!

I took my CHEVROLET CRUZE 1.6 LS in for its 60 000 km service when it was still on 58 000 km. Westvaal Motors in Potchefstroom refused to make an appointment because the car was not serviced last year! Why should I service a car when its not yet time for the service? The Service book states that the car must be serviced every 15 000 km and the car was serviced on 45 000 km. I think Westvaal is taking a chance by expecting me to pay for a service when its due now. They want to save money and make me pay. I am very very disappointed with the service I received in the company I believed in. Please assist in the matter as the car is about to reach 60 000 km and I am not willing to pay for a service that is due to be done by them. They are not getting out of doing their job so easy!!!!