Telkom mobile bad service

Telkom is charging me R207 more on my bill because I missed a payment..as per consultant. I made several attempts to change my bank details and I kept on being mislead by Telkom staff. I tried calling but struggled to find an option to speak to someone. Telkom at Forest Hill logged a request for me to be called back but no one called. I also sent a request on the website but no1 called me. Now I'm being penalised ...bad bad bad service. I have never missed a payment