Inso Aluminium Gauteng
Not attending to defects of product

I have purchased set of aluminium windows for a new house and fully paid, "Inso Aluminum" is not attending to defects under warranty for windows (months of communication, no result)
Also bought stainless Steel Balustrades, with very poor craftsman ship and faults, and according to registered inspector it has to be scrapped and is unsafe, They refuse to attend to their problems under warranty.