Robust ... not prepared to make good on poor workmanship

I had a pool installed 4 years ago. The pool is clearly defective as it is forming lumps which should not happen in a new pool. Further, all the grouting has worn away from the paving. Apparently my fault for splashing water? It is a pool! I am now going to spend a huge amount repairing both the pool and the paving. And the response I get from Robust .. “well you can’t keep everyone happy”. This is not acceptable. They have made no attempt to rectify the situation, but have only trotted out their very short warranties. Stay away from them!