Beware of poor service and financial holdfast on customer

In October 2012 I had a electric garage door installed at my house by Hyperdoors Worcester. Since then the hinges on the 6 panel door broke 3 times. The first was while door was still under warrenty where all the nylon hinges of the middle panel broke off and halve of the door panels fell on my bakkies windscreen with significant damage. The hinges was replaced with metal hinges free of charge and now these hinges broke again. They charged me to replace the hinges again over R4800.00 and I had to pay 80% in advance before they would come out and asses damage even though I spoke to the owner Mauritz Krone and expressed fears that the door might fall on my kids again. He said its was due to poor maintenance or that I drove into it. When his repair guy came, he noticed that all the hinges was cracked through holes in hinges were no *****s was put in. Each hinge had 4 instead of 8 *****s in. He replaced them with double hinges on the sides of panels instead of single row that was put in on previous 2 installations and put 8 *****s in each hinge as it was suppose to be done in the first place. My door panels also blistered within 2 years from installation and had to be replaced. Is this fair to spend so much on repairs of a door that is not yet 5 years old. Fortunately I've taken many photo's and kept hinges for evidence. They charged the full amount for travelling to 3 customers in our town and worked at at least 3 different locations without splitting the travelling fees. Labour cost is R228 PER FIRST HALVE HOUR AND THEN R 320 PER HALVE HOUR. They spend only 1 hour at my place, but charged me R 2500 for labour. Is this fair?