extra line on account,debited with no credit.

My boss noticed in Aug/Sep 2015 that he's been debited for two lines, we requested for the other line to be cancelled because he was not even aware that there is another line and that he has been paying for it for 4months. It took almost 2 months for someone to respond and try to get all this sorted. During the month of February i was told that the other line on the account is been cancelled and that credit was done on the account, i asked for proof on writing of some sort which i did not get. Today is the first and again telkom debited the account for two lines. Why do we have to struggle to get this sorted when it wasn't us who messed up but every month you keep on debiting while clients keep complaining with no help whatsoever. Telkom please do something about this. Its been 7 months now and nothing is happening!!!