Lifetime warranty not!!

My bakkie was in a minor accident and the bumper was repaired in 2017. After 4 years the paint job is starting to peel off in multiple places. Knowing Proline has a lifetime warranty on their workmanship I took my bakkie back to them for review. The mechanic Eddie had a look and accused me of damaging the bumper again and refused to help me. Looking at the bumper you can see multiple areas of cracking and peeling off of paint which is a sign of poor workmanship. If the bumper was in a recent accident you would have localised damage. I am upset in the way I was treated by Proline and was shown away. If Proline cannot live up to their promise they should not give a lifetime warranty. They are very happy to help with a new accident claim but follow up care is useless.