Vehicle sold under false pretensions

I bought a Ford Fiesta 2014 model cash in 2016. The vehicle had 19020 km on the clock. I was told that it is still under service plan and guarantee. Now the 5th of August i wanted to book it in for a 40000 km service. at this time of booking the vehicle had 39600 km on the clock. All of the sudden i was told by Barlow World in Alberton that my vehicle service plan and guarantee had expired on the 5th of June 2018. Last year June the vehicle was service. Why did the service advisor Tanja not told me i need to service the vehicle before a certain time. i am not impress or happy. i wrote an email to ford south africa and even them could not assit me. they told me it is company policy and rules