Bumper problems of the 2003 Kia Motor Spectra

Front bumper cover coming loose on 2003 kia Spectra with 38,050 miles. Due to the cover coming loose, the inside plastic wheel well also came loose and rubbed against front tire damaging both the tire and the the plastic wheel well. Vehicle has never been in an accident and shows no signs of structural damage per kia dealer and outside mechanic. Kia refuses to repair under warranty claiming that the front bumper cover coming loose and causing this problem is an "adjustment issue". The outside mechanic and I believe this is a not an adjustment issue, rather a manufacturers defect and a likely safety issue. Should the plastic wheel well have came loose on the highway it is possible that the friction created from it rubbing against the tire could have increased the tire temperature in such a way that could have led to catastrophic front tire failure. I would like this matter corrected by the dealership as part of their (ironically) bumper to bumber warranty.