Minor service , and now no warrenty

I bought a car from rock solid and paying on for three years , took car in for a few repairs , the warrarnty has run out and won't fix it . Rock solid has fixed minor things on my car after warrenty supposing expired , I did not pay . And now car is almost paid off which I thought it was a 3 yr contract and they are telling me it's a 3and half yr never heard of that . Rock Solid explained to me when I bought car it was warranty I was buying not the car . So why would I pay 7,000 plus for a 12 month warranty , sounds crazy ! So I guess they got me .