What am I paying for

I have a Telkom ADSL 10mb uncapped line. My line went down to 2mb in November 2017. I reported it on 29 November and was told they fixing the line. However December it was still not fixed. I reported it repeatedly during December 2017. Still January 2018 I'm still waiting with my line down to 0.22mb. I've now been again been charged full price for a line not working ....what am I paying for?