Total lack of responsibility

I cannot believe the lack of responsibility by this company. I am on a month-to-month contract and unfortunately due to being paid late in January, my payment to Telkom bounced. Unfortunately, they have massive penalty fees. I paid them as soon as I was paid which was probably 2 days late but unfortunately still got charged the penalty, fair enough. I then started getting bombarded with SMS's stating that imminent legal action would be taken if I did not pay this bill immediately - which was actually only my next payment coming up with the penalty fee added in. There were also some calls that I assumed were Telkom but Truecaller picked them up as spam and I am unable to answer calls during the day. It clearly stated on the invoice that I received that the amount would be debited on the 29th of February so why was I receiving all these threats?! It also stated on the age analysis, that I didn't owe them anything just yet. But then, come the 29th of February, they did not debit my account. I then paid the account knowing that this amount needed to be paid. However, this would take a day or two to reflect and I have now been charged a penalty again. During all of this, I had tried to find an email to start a conversation with someone about this but they don't have one for customer care or at all, I went on Twitter and they are so lazy that they have a bot who answers for them, and is useless at that because at some point it just stopped responding. Then NuDebt who is their finance company, whom I eventually spoke to, asked me to WhatsApp proof of payment to them which has not even been acknowledged. They just keep passing the buck. Not everyone can phone calls during the day and most companies will have a customer care email address that you can contact in this instance.