Wrong bill for 600£ charge for using landline which was never used

Hello,

Ive been using virgin from almost 2011.

I was paying 60£ almost last year, and then asked them for suggestion for reducing. they setup basic account and reduced the bill to around 45£. I use direct debit to pay the bills

I am working from home most of times after covid and redundencies happening in my work.

I wanted to finsih some work on Satday and internet went down. TV also stopped working.

When I call , the automated msg asks me pay 600£.. What !!!!

They whole sat day, sunday and today was transferred from one dept to another. Nobody helps.

I told I need some technical engieer to visit me, to show the phone was not working. Gets transferred from customer to collectios team. Im not sure what should i do about this..