Failing to repair Tablet

I submitted a complaint no so long ago, quite frankly I am done with this company they are very inefficient. It took a complaint on Hello Peter for them to take me seriously but they are still messing me around. I paid excess as was expected of me for my tablet to be repaired, I received it and the screen was fixed but it was not switching on and not charging. They sent an email today that I have to pay excess again for my item to be repaired whereas it is their fault, I hadn't even used the device because it was not switching on but they said they had checked and it was charging before they sent it back. I reported the fault the next morning upon tryimg to charge it overnight and it was still not charging. How can I be expected to pay excess twice, because when I got it, it had not been fixed. They should've fixed it and made sure they did it right the first time.