Telkom Billing the worst!!

Telkom is the worst when it comes to customer service/experience. They debit my account even when I pay my account before the debit order date runs. I used this method to pay them for a year without them debiting my account until recently when I saw their debit on my account. When I stopped them from debiting my account they handed my account over to debt collectors with amount I don't know it comes from, without even contacting me or communicating with me whatsoever. Their contact form does not work, their line does not work. how are we supposed to query our accounts with them? I am beyond disgusted with this network provider!