Refund/Return of Kiddies Tablet under warranty

Totally unacceptable experience. I bought 2x kiddies Mi Mate tablets December 2017. Both were delivered on the 15th of December 2017. These tablets were Christmas presents for my 2 children. (boy and girl) Ive ordered 1 blue tablet and 1 green tablet(no pink tablet available). The order went through as MiMate KP12G 7" 8GB Kiddies Tablet - Green. Qty: 2 These tablets were packed in the same parcel/box. Once Ive received the parcel, I wrapped it and kept it for Boxing day, 26 December 2017. On that day we opened presents and to my surprise there were 2 blue tablets. Thinking nothing of it and with the package already opened, I kept the second blue one (supposed to be green in colour) and on Boxing day I couldn't take away my daughters present. The one tablet became defective and wouldn't turn on. I lodged a return through Takealot's website. On Tuesday 13 Feb 2018 they came and picked up the tablet. On 19 Feb 2018 they informed me via email that they could not accept my return as the tablet I returned was blue of colour and not green. I was disappointed and explained to them the same story as mentioned above. My concern was that the colour has nothing to do with the functionality of the tablet. The tablet was defective and I wanted a return because this product is of very low quality. They refused to help me because of the colour and returned the broken tablet to me on 21/02/2018. I have all the emails as proof. Another concern is if the other blue tablet becomes defective I wont be able to return it as well because it was also send to me in the same parcel marked with MiMate KP12G 7" 8GB Kiddies Tablet - Green. Qty: 2