Bad service from Supersonic

I currently have 3 lines from Supersonic. The last one I app**** from on the 26th November 2022 and paid the amount as required. On the 28th November the debit order for the other line was deducted. On the 1st December Supersonic deducted a double debit order amount instead of only the pro-rate amount for the 4 days. The unit was delivered on the 27th November 2022 so meaning I only had to pay for 4 days. The full amount paid on the 26th was for the month of December. I have logged a query and try to phone them but there is no other word as totally pathetic the service they give. On one call I was told to hold on and after 25 minutes the person still did not come back to me. How must I resolve issues if this is how Supersonic treat their customers. Would also like to mention that I pay for my service every month!! They even say you can ask them to call you back but this NEVER happens!