Incorrect billing & bad service

I did change of ownership in Nov 2019 & my requested was not attended until I have to re-send my email to the change of ownership in the form. I re-sent the email on the 06 Jan 2020 Only then my request was attended to. Now the previous owner paid the fees for Jan 2020 but on the new account where decoder was transfered to was also charged . I ask the agent on the 21 Jan 2020 why is this. She responded rudely and advised that I had to pay it if I want my services opened again.??? I was shocked which she ended up dropping the phone. I then called again and got a better service but I refuse to pay cash when my account is on debit order. I asked why double payment?? the lady said when you are doing a change of ownership you are charged a fee. Unfortunately this is not on their business form nor anywhere in their website. The lady said unfortunately now she is telling me & I have to pay..What a shock...I refuse to pay double..This must be sorted