Complain for damage goods

Good afternoon, on the 14th July 2014 I bought 2 Dunlop tyres size 255-40-18 with alignment from Machine car care centre which is part of the Middle East group of Companies in South Africa.(VAT NO ***. PTY ltd k***). After using the tyres for 4 months I realize that the tyres are completely finished. They were worse than the one which was in the car for more than 12 months. I laid a complain and I was asked to return back the 2 tyres which I did and they acknowledged revived the tyres and signed on the 22nd December 2014 so that they can take it back to Dunlop. I personally called Dunlop head office in durban and they asked my reference number which I did not have, I then asked the branch manager Mr Binish Ganapathy who told me that the person who send my tyres is on leave and he will call me back. Since January 2015 up to now he is telling me the same story. Please assist me