Refund on Tablet

cris01

a cloth caeHello, I just wondered if anyone could help with this....I bought my daughter a tablet off Amazon (a compancy called A1CS Ltd)for Christmas. It was originally bought in November, but not used until Christmas day. She had had it about 3 weeks when it stopped charging, the company advised to return it, which I did. They sent a new one, that lasted about a week, then something went wrong with the software. Again I could not update it from home, and had to return it. They supposedly sorted it out, we got it back on Friday within 2 hours of receiving it, a recurrent message was comming up and we could not get it off the screen. I sent them an e mail advising if I had to send it back again I wanted a full refund, it is costing me postage every time I return it. Again they advised to download a software update but I could not do it as the screen was frozen. I sent an e mail saying I was sending it back for the last time, I wanted a full refund or else I was going to complain to Amazon. My daughter is only 10 with learning difficulties and this was supposed to help her educationally. she has hardly had any use out it! They have refused to give a refund for it saying I have had it too long. They have offered £8 towards postage and a cloth case/screen proctectors. What are my rights legally regarding a monetary refund? Thank You