Fraud account set up in my name

I believe a fake ID MOBILE account has been taken out in my name. I recieved a final notice letter in the post from ID MOBILE claiming I had an outstanding balance to pay, despite having never had an ID Mobile Account. I’ve submitted a report to Action Fraud but need to get in touch with ID Mobile about the payment due to avoid having a debt in my credit record. What is the best way to get in contact with ID Mobile about this to get this rectified and so I can report this and have the account closed? There is no contact number and the chat only takes me to a BOT. I’ve seen others having the same problem, and an investigation has been opened. Please help!