Over Charge on account - Refund delay

I have been querying a refund due to me from being overcharged from March 2025 where I was incorrectly billed. I began to query this in July 2025 and only in October 2025 Cartrack confirmed the error and advised that I will be refunded. Yet another back and forth ensued and only in December it was confirmed that the refund will be processed. On December the 4th I received a call confirming the refund will take 14 working days to reflect into my account. On the 30th of December after not having received the refund, I sent a curtesy email to follow up on the status of the refund. To date no response to my email. I then sent another follow up on January the 2nd, and today being the 5th of January 2026 I have still not received the refund or a response to my emails. Upon calling them today I was then advised that the query is still reflecting as "open" on their system and therefore the refund has not been processed as yet. What worries me is the fact that for so many months they were not able to pick up they are over charging me, and now there is a delay in a refund they have acknowledged. If I had not picked it up, how much longer were they going to overcharge me? How many customers are also being overcharged. For me to also chase a refund for close to 6 months is really unacceptable. Can Cartrack do something about this, not just for my account but for other customers having the same issue or going to experience the same issue in the near future.