Telkom is *******

So today I got an inv from telkom stating we owe them R902 rand but last month we paid everything that we owed so I called them and asked them why then they want to come and tell me it's for late fees now first of all the wifi service works one week a month mostly I can't connect more than 3 devices to my wifi then it doesn't want to work so what the he'll im I paying for one **** service and they can never tell you what's really going on I want to cancel my wifi I'm tired of paying for a service that never works they can take me to court then I wil ask the judge what I'm I paying for because it never works but telkom is quick to hand you over but not quick to fix there problems!!!