Being Charged for a Fiber line in a house i don't live in anymore

I had my line moved to a new house and was still billed for the line that was cancelled in the new month and now I'm being asked to to pay again for my new line in the same month. Spoke to 5 different agents on their WhatsApp helpline and they denied my credit query, No agent can help me and they have sent me emails to say they will cancel my account if the payment isn't made by the end of the month