Service plan for my Renault

I took out an extended service plan on my Renault Sandero that I bought in December 2014. Registered in 2015. The plan was for 5 years or 45000km whichever comes first. I drive very little and my first sevice was done in 2015 on 4245km, my second service in 2016 on 8716km, my third service was done in 2017 on 15374km. I took it for it services on the year period instead of the kilometers reached as it never reached the 15000km. The equirement is that it should be serviced every 15000km or 1 year whichever comes first.

I took it in for its fourth service December 2018 on 19800km. They refused to do it under the service plan as they said it reached the 45000km. They said that if I had it done in 3 years the services for a 15000, 30000 and 45000km were done on the vehicle and therefore the service plan expired. In other words in no way could my car have been serviced for a 5 year period of time. This is a breach of contract.