ESA telephone appointment without a time

Hi, I’m hoping someone could answer a question for a newbie please. I applied for new-style ESA in August last year (2021), back-dated 3 months to May 2021. I haven’t had an outcome or assessment and got a letter last week telling me I can’t get ESA after May 2022 unless I’m in the support group. Then this morning I got a letter for a telephone assessment… but the time says between 9am and 12pm! Is this allowed? Most people on the forum seem to have a proper appointment time and I’ve never heard of this before. I struggle to talk on the phone even on a ‘less bad day’ so will go to pieces having to wait all morning. I have severe PTSD and depression, and like most people, had hoped I would get a paper-based assessment as I sent lots of evidence including reports from 4 different medical practitioners all saying I’m not fit to do any work at all up to my normal pension age in 10 years time. I don’t get any actual benefit because of my occupational ill health pension but need to claim for national insurance credits. (I’ve also just sent an application in for PIP so probably will have to wait until Christmas before I hear about that). Sorry to rant but any advice greatly appreciated.