Kia Warrenty?

purchased used kia rio still under warrenty, have had it less then a year has been back to dealership 3 times for same thing, and other times to. this last time the warrenty people charged a 100, deductable. the only reason they should have to fix the same part 3 times is either the dealership does not know what they are doing or there is something really wrong with the car. got this car for my grandaughter because she works nights only to learn we cant trust this car. the dealership does not give us any help. brown and daub in easton pa.