Defective doors

I purchased four town house doors from Buildrite in hammersdale in the month of August 2015. The doors were immediately installed in my new house in Westville. In November 2015 all the doors began warping and the the masonite timber started separating from the rest of the door. At this stage my house was completely build and the doors were not exposed to wheather. When I took this matter up with the store they refused to do anything about it. I have spent money to have theses doors installed and now I'm stuck with doors that need to be changed. It is not fair that the store cannot take responsibility for this as the doors were only three months old. Buildrite is not a reputable store to buy from so beware of low prices they offer.