Worst customer care experience

I have received the worst customer care experience at MTN. I app**** for the Internet monthly contract deal I received a modem and struggled to connect for over 3 months whilst MTN was sluggish to assist. Now I managed to connect then I'm told the monthly contract is cancelled, I am still being billed, I have paid all the bills even the current one, now I keep.beinh told I must pay my bills whilst I have no internet connection. What am I paying for exactly because for more than 3 months MTN kept sending me from pillar to post struggling to connect the internet., and this is the poor customer service I get.