Change of banking details failed 2 months

I have been trying to get hold of telkom for almost 2 months which is practically impossible. I even went to thier store in Vincent to try and change my banking details. I was told to contact 180. I've called several times but I am not winning. R200 is being added to my bill for debit order failure. Do they at least consider the fact that it is impossible to get hold of anyone from telkom..........!