Bad service

bought a tv set about 2 years ago, now the tv broke and i took it in for repairs only to be told it cant be fixed due to negligence (the motherboard broken), this was during the time of loadsheddding, now i told them i dont want it back as they cant or dont want to fix it. yesteday they came it dropped it off at my home but they left it on the ground outside then my child who didnt know it was lying there outside accidentally trampelled on it when she was running outside. now to screen is all broken due to this. i feel although the tv was broken due to there negligence its all messed up now and i left it outside as they left it there without my consent or knowledge today they call me for payment (what to do now). Also i have seen that my account is all messed up lets say last month balance was R3000 and im paying R600 each month now to balance just came down by R200 (Please advise)