Quick to debit not quick to refund

My daughter has taken out Flte with Supersonic and all was ok, we then decided to take out Airfibre. The Airfibre was installed and activated and Flte router taken this was round about 15th of the month. Charges now being debited should have been pro rata for Flte and Airfibre, however was billed full Flte for the month it was taken away plus full sub for the following month and still pro rata air fibre and full sub for air fibre. This has been going on since March 2022, numerous phone calls and no one ever gets back to resolve the query and no credit note passed to date...🤔🤔🤔