Restons chasing debt set up in my name fraudulently

[Supermoo19]

Hi all. I've had a pre action letter from Restons Solicitors about an energy account that was set up in my name without my knowledge, 3 years AFTER I vacated the rental property in question. Having spoken to the energy company, they confirmed that the account was set up in my name by the landlord, via the letting agent for an tenancy start date 3 years after I moved out.* The energy company have been great, and after speaking to the lettings agents (who also confirmed I did not live at the property when the debt was accrued), have removed my name from the account. Apparently their debt team have spoken to the debt collection agency that instructed Restons. I have had no comms from Restons however, who refuse to reply to mails and even claim they haven't had any. Last week I printed the email confirmations from the lettings agent and energy company to confirm the stuff above, sent it recorded delivery, and still no word. QUESTION: I have until 2nd Jan to respond to the pre action letter. Should I do so and dispute the debt, citing the updates above? I have also registered an account with Action Fraud UK to try and sort out how on earth the energy account was created in the first place.* Thanks in advance for any advice.*