Disgruntled with after service

I have had roof windows installed by Tony Sandells Roof Windows. When they installed the windows, they were efficient and did a very nice job. They are supposed to be a very reputable company. One roof window they installed from scratch. In another area of the house they installed another 5 roof windows. When it came to the second 5 windows, they had to remove 5 x small windows and replace them with slightly larger roof windows. After everything was finished I needed an A19 certificate for the roof. A19 inspectorate came to inspect and to advise what problems in the roof needed to be redone/repaired in order to obtain an A19 certificate. They spent many hours inspecting every section of the roof throughly. They gave a report on their findings and amongst other things that needed attention, they reported the following: "During our inspection, it was noted that several trusses over the flatlet section has been modified, where webs were simply cut out in order to fit the said skylights. A remedial design for this section has been done as seen attached as Appendix A. The North Eastern hip-section showed this same cutting of truss detail, especially to the truncated truss supporting this section. A remedial design for this section has also been done, please see attached, Appendix B. Please note that a final inspection will need to be done on completion of the remedial details as stated above for certification purposes." A roof company came and repaired all the things that needed to be repaired in order to be able to get the roof certificate. They were efficient and I would recommend them to anybody. I asked them what the cost was of fixing the damage caused by Tony Sandells Roof Windows and the amount came to R15,551.62 The original cost of the whole installation of roof windows was around R70,000.00 I emailed TSRW and told them of the problem and asked if they would please reimburse me for the money I had to spend to fix their error. After months of backwards and forwards and stalling, they were prepared to take responsibility for the one skylight and reimburse me R3,110.32 as they felt that the other 5 skylights were not installed by them from the beginning. They had to remove the 5 original ones and reinstall 5 slightly larger ones. I told them that I did not understand as according to the inspectors the webs were all modified in the exact same manner so they could not only take responsibility for one. They then said they would discuss it with the roofing company which they apparently did. They came to see me and I suggested that they go and speak with the inspectors who did the report. I have also asked them to adjust the one skylight as it does not stay open. They said when they next had someone in the area they would see to it. This too has not happened. Since then, my emails have been ignored. I then emailed to try and get a cut off date for finalizing this saga and was ignored. I then sent an email to say that I had not option but to take further action as this whole saga of backwards and forwards and ignoring has been going on for 6-7 months.