Cancel mi assist and contract with cell c

Im still waiting for the person to call me to cancel mi assist thing im so disappointed ???? The lady called me and told somebody from mi assist will call me im sick and tire of this thing Im want to cancel my contract with cell c because you can't tell me you can't cance this thing because you guys gave them our information and the debt my money with your monthly installment im tired I want to cance everything now its been 5month now