Makro and its poor choice of suppliers

So i bought a chair and since about 3 months after i got it i have been having problems makro sent people out apparently from suppliers who saw there was a problem and said they were going to replace the mechanism . After about 6 months of posting on hello peter eventually makro sent the same people back here who have stated that i tampered with the chair which is utter nonsense saying i must pay R200 for them to replace the mechanism because of my tampering. Why would i mess with a chair under warranty. I WANT MAKRO TO TAKE THIS CHAIR BACK AND CREDIT ME SO I CAN TAKE MY BUSINESS ELSE WARE.