No service from cell c

I need to cancel an account of mine, i went to a cell c store and they advised i do it by phoning 084 143, i have been attempting to do so for 4 days now. Everytime i hold on for up to 1hour, without the call being answered. No other call centre or agent can help me, i need to phone that number, without any success. I need to cancel my contract before tomorrow, but cell c service does not allow me, because they just dont answer. This is the worst service from cell c.