Very poor window sliding doors - Aluminum corroding - extremely bad workmanship

Econo Windows Cape Town has installed 3 sets of sliding windows. I have been extremely unhappy with them from the start. The glass is vibrating in the wind and they are difficult to slide. The representative was here to install new rollers and paint the frame. The paint of course did not last and the movability did also not last. Now a couple of years down the line, the aluminum frames are corroding and the coating is bubbling . I have been in contact with the company non stop since January this year, nothing has been done. I expect a decent replacement and reliablity in fixing this problem once and for all. I will not except another shabby quick fix.