Wrong payments not rectified

From July 2021 up to September 2022 Citiq has paid the money they collected from one of my meters to another person. On first October 2022 I informed them of their mistake and asked to be paid all the money they owe me for the 15 months of missed payments. At the end of the month I did receive the amount for October, but no news of the refund. Interesting to say, in the first week of October I received a phone call from them assuring me that I would be paid, and the matter was in the hands of their finance department. Obviously nothing written was received by me. Since then, they just ignored my request to be reimbursed.