Awful back up service

what started as a honeymoon, ends in a divorce! reported a problem with my Samsung air conditioner within warranty period. was told to get a report on fault from my technician so they can submit warranty claim. claim was then approved and they charged me R300 to deliver the replacement part because they said they did not install the unit..... Unit is still defective after paying my installer to fit part, remember unit still under warranty but the customer has to pay the labor... unit still showing fault, now they want me to pay them a call out fee so they can inspect the unit because yet again, they never installed the units. i explained that this has nothing to do with the workmanship, it is a Samsung factory fault. why must i the customer pay for the labor and courier charge for a item that is still under warranty? where was this in the terms and conditions when i purchased R130 000.00 worth of Samsung units from them?