I am never using technomobi.co.za ever again

I bought a phone from them and it got delivered a few days later. When I started using the phone it kept on restarting during use. I contacted them they advised I send the phone back. They apparently took it to "repairs" and they said they found nothing. They sent me back the phone, and now it is stuck and blank and says that the phone is *******. I've barely used it for a few days and its like this. I regret buying with them. I have emailed them with photographical proof of the error on the phone but still haven't received any feedback.