Urgent Query re. ESA to UC Managed Migration - Extension needed

Hi,

Please can anyone advise me on requesting an extension for my ESA to UC managed migration application?

I've had a difficult time with my health recently (flare-up of long term condition) and am struggling to to get everything organised to apply for UC. (Still to open UC account).

My IR ESA (Support Group) is due to finish and I need to apply for UC by end of this month.

This morning I have been sent a text from DWP saying that they will call me in next few days.
The date/time was not given, although the phone number the call will come from was provided.

I am often not well enough for phone calls and am feeling completely overwhelmed and am concerned that I will have to apply for UC over the phone when I am not prepared.

Any advice would be greatly appreciated.

Thanks.