Outstanding account???

September 2019 I received an account from Telkom showing that my long outstanding query, since November 2017 had been fixed and my account was in credit for the about R188. I now find out from my bank that as at 31 Dec 2019 I have an outstanding account of R2200 for which I have no details. I have tried to contact Telkom by calling, sending then a WhatApp and using the Twitter DM service and all have failed so I am now stuck.