Bad service

I bought a 7" kids tablet on 18Aug. the battery of the tablet didn't last long. unfortunately my son had broken the wing cover that came with the tablet however the tablet was unharmed. the tablet came with a 12 months warranty. I returned the product only for them to tell me that they cannot help me because of the broken cover. I had asked them to please change the tablet and put it back in the broken cover but they didnt help me. Tshililo, the consultant whom i was speaking with through emails, even added to say the warranty is void and until today he/she isn't answering me emials