Took a service plan for 2 years and they have been trying different tricks each time to not pay for my service

I took a 2 year service plan and each time I need to service my car they use different tricks to not pay the service. The plan I had was for 2 service (24 months) all paid in advance, today I am told my plan expired in August 2017. This is a surprise because when I took the plan the agreement was for 2 years and I have taken my car in 2016 it was due again sincerely my car has 15000 km interval so according to them now I shud have took my car back for way B4 time. I am really disappointed, in the 2 years I have been with them its been a nightmare and would not recommend them to anyone. I am looking for a different service provider as I will not continue with them due to the errors and ***** ****s they come up with when it time to provide a service.