TRIMTECH petrol lawnmover

I bought a Trimtech Lawnmower 25 November 2014 from Game Mafikeng. In May 2015 the lawnmower lost power and just died. Took it back to Game and they sent it in for repairs (it was not even 6 months old and still under warranty). I got a phone call today from Game that stated that they fixed it but I have to pay R1600 (It cost R2400 for a new one) because a damaged blade damaged the engine which they say is due to customer abuse. That is TOTAL BULL, We planted new grass, and we have no rocks whatsoever on our lawn so how can a blade get damaged from just cutting grass for which it was attended (best of all is I did not cut grass in December because we were away, and then every 2nd week since then, and only once in May, which is a total of eight times). I have seen about three other complaints on hello peter on exactly the same issue, each with its own excuse for not fixing it. There is no way that I am going to pay R1600 for something which is clearly a manufacturing fault.