Debit order spriked from R149.00 to R596.10 - 7 weeks later still fighting to sort.

I have been having a vehicle tracking policy with ADT Secure Drive – from July 2019. I was paying R149.00 per month. Suddenly in February 2021, they deducted R596.10 in two installments. I called to query the sudden spiked instalment. I was told my policy was due for a 10% increase some months ago – they decided to back-date and prorate whatever I should have paid. Sadly still, they miscalculated. I was promised the refund of R596.10 and proper re-calculation. Next thing, I was promised the refund of the access deducted. NO REFUND STILL TO THIS DAY. The next thing I get a call from debtors department, claiming that my account is behind. To make it worse, I even received a call from some lawyers (debt collectors) claiming that I owe their client, ADT Secure Drive. I wish ADT Secure Drive can just sort out their admin, get right calculations and process whatever refunds due to me; if any.