kia hatfield

i bought my car from kia hatfield about 6 months ago. opel assenta. 1 month ago my car went for a service. i complained after the service the car overheated. they looked at it and was pump of water that did not kept the water level. now 1 month after the service my car over heated and went dead. i had towed in the car to kia. now i am informed it was my fault the car over heated and the warrenty does not pay<br> i must pay 6000. the car is still not registed on my name