I have a contract with Herotel to provide my internet

I have a contract with Herotel to provide my internet. During late last year, my internet was suspended as I could not afford it that month. The 25th of November Herotel was paid, and our internet was switched back on. Installments were scheduled to go off as normal on the 1st of every month. January 2022 came with its monthly installment and Herotel gave me suspension notice. When I called them, a woman explained that they did not deduct their installment for December. This was their fault. I did not notice this until I investigated and checked my bank statement. This is bad. A mistake on their part and now threatening to suspend my internet because of that. My wife works from home. We cannot afford this and another R998 this month. Its ridiculous.