fondi wi fi table

i bought a Fondi Wi fi by Cna, lasdt year end Nov 2014. they said they have problems all I need to do is keep the charger in, so it doesnt run flat.<br> I gave the tablet to my son on Christmas, he used it for to days. then he went away. on the 6 Jan i wanted to put on the tablet. I needed to charge it, so i put on the charges but it didn't want to charge or go on. so i took it in on the 6 Jan 2015 they also try to charge the tablet. they also had about 12 of the same Fondi tablets that has problems to give in at Sahara. I phoned to weeks later to Sahara, they said they had a back log. every day i phoned but still not any answer the end of Jan i received a call from Cna, so i went in to collect the tablet. The lady said to me i need to pay R535 for them to fix if. the tablet cost R549.00. i told them they must give me the tablet back and ask why must i pay to fix the tablet if i only have it for a month. i have phoned them again last week when will i get the tablet back, they have till today not phoned me to collect the broken tablet or if someone is going to fix it. its been more than a month that they have the tablet. what can i do.<br>