Poor service from Mayfair Gear Boxes

I took my truck to Mayfair for gear box repairs and I paid R 138k for the work when I tried to hook the trailer the truck was not tipping making noise from the gear box I called Mayfair and they sent someone to come and check and they advised me to bring the truck on Monday yet the problem happened on Saturday I told the technician that the truck was surpose to go and load sarturday evening and he said that his supervisor will call me to see if they can help but up to now no one has called me. Which costed me loss of income. To my surprise the gear box has a sticker that it was tested and passed. So in the case of my loss I think Mayfair must be responsible. Because this is not the first time taking the truck back after they have said they have tested everything and quality control has been done. Ref DL06DVGP. Check your records.