Telkom
The Settlement account is incorrect

I made arrangement to setttle my telkom account 349901101178, on the 21 January 2013, they send me a sms on my cell thanking me for making arrangements to settle my account, the amount is R582.87, two days ago i finally received a statement in the post, but in the statement they were telling me that my settlement amount is over a thousand rand, i want to know how did it get to that amount, there is no way that my account is that amount, i would like telkom to correct it, if not i would like this line disconnected