Please help me

I bought a mecer guru laptop from them they deliver it when I opened it found out that the simcard tray is not working sent them sn email even sent the laptop back to east gate mtn shop now they are billing me for something that I do not have I want mtn to cancel all my contracts thru are ****** they gave me a router saying am gonna receive 120 GB to my surprise I am receiving 20 GB so they keep on lying to me I want nothing to do with MTN they are ****ed up my nr ***