@Representingpam,
Your post won't reach staff attention on this old thread.
There's also a problem posting on the forum in that the community staff cannot yet sort out issues for former Shell customers - hopefully that will come, but for now you need to be asking to speak to the Shell Migration team whether using Chat or the phone [03451 720088, 9am till 6pm Saturday].
If you have Power of Attorney, you usually have to send proof to each and every company that the person you represent has dealings with. So that would need to be sent to the debt collection agency.
If it's a relatively recent PoA, this can be done online, rather than sending documents in the post:
https://publicguardian.blog.gov.uk/2020/09/09/use-a-lasting-power-of-attorney-your-questions-answere...
If you are simply a Nominated User, you'll need to check with the Shell Migration team that you can represent the customer when dealing with the debt collection agency:
https://community.talktalk.co.uk/t5/Articles/Nominated-user/ta-p/2205256
If you need further clarification on the forum, please return to the message board [choose billing, not Home Phone from the Help with your Service options in the forum menu]; click on start a topic to begin your own thread and staff will respond after the weekend. They won't be back on here before Monday.
You'd also need to complete your community forum profile in the Personal Information area with YOUR details and, lower down, complete the full details of the lady's name, address, Talktalk phone number and account number in Private Notes. Scroll down further to SAVE CHANGES.
Gliwmaeden2, a fellow customer.
