MTN Nigel

I got a new contract with a Hisense phone and everyday for about 4 to 6 hours I can not make a call and can not receive calls. The excuse NO SIGNAL. My wife got the same phone with Vodacom great service and signal. My son is also with MTN no problem with signal at all. Now I want to know is my money not good enough for MTN that I can just get half a service or must I just pay halve of the Contract because I only can use Halve of the Contract. It does not help to go to Nigel MTN all they say is we will look in to it. No problem gets solved so please I need assistance with what must I do. Sorry there is no negative stars to mark because I will give MTN a negative of 10