Poor service

Bought a 55 inch hisense at hi-fi corporation in toti last year, last week the TV set showed lines throughout, as it is still under warranty I then took it to the Newcastle branch for repairs,I got called and was told,they not going to fix it since I had dropped/damage the TV ,however they are failing to show me evidence on the exterior surface as it should be evident since according to then I dropped the TV set.