Preventative maintenance

We reside in an apartment block in Cape Town , and Metal Windows replaced our wooden windows with aluminium windows 6 years ago. The 5 year guarantee has expired and certain issues are now evident after 6 years. We contacted Metal Windows and a consultant undertook a site visit. Subsequent to the receipt of a inadequate quotation, and further correspondence with Metal Windows it appears that Metal Windows is not in business to undertake paid maintenance on their windows.