Support to wrag in 5 days?

A friend from my self help group received a transition from IB to ESA of support group and on phoning to find out the review date was eventually told it was on their computer for a date in 2015 (I cannot recall exact date she told me). Anyway she has now received a letter re xmas bonus and reference to her being in wrag. She phoned them up and oh yes the first letter was a mistake she's in wrag?!
She really is very ill and I was not surprised she was in support but am shocked at what has happened and wondered if this happens often and what should I suggest to her. My own thinking would be phone again but maybe something more formal is required?
Thanks
dollypond

Ps Forgot to say that even though the decision letter was received this month, she was told the decision was made in August therefore the 12 months contributory 365 days started in August even though she has received IB until now!

Gordon, Thank you very much for your reply. I have phoned and told her and she feels a bit better re the date of transfer and is considering complaining and asking for a reconsideration. I will post what happens here when I find out. My migration is next year so this has freaked me out as it sounds so shambollic!
Thanks Again
dollypond