PIP review face-to- face assesstment

I have multiple conditions that are long term.
I was awarded PIP (standard daily rate) few years ago after assestment (no appeal).
I received a review form for my PIP claim.
I followed the guides on the website and on the form wrote "no change /same" then went through repeating how I'm effected like I did on my original form.
I supplied them with a doctor's letter confirming that my conditions haven't changed since the last assestment.

however I still received a face to face appointment.

needless to say I'm very upset and streesed as I rely on the PIP payment for rent topup and to avoid benefit cap too.

is this common to call people again for assesstment even when theirdoctorl confirms there has been no change and after they thmeselves award them PIP based on those conditions before?

Thanks for you response,have you seen any case where they cancel the face toface assessment and do papaer based review after client call them and complain?
I wonder if there is any hope in doing so now that they have booked an appointment for me.

Just to update,I telephoned them and asked them why they didn't do the paper based review despite no change in my health and GP letter confirming this;after speaking to a case manager I was told they will only consider paper based reviews if there is specific evidence letter from doctor saying that attending face to face assessment is deteriorating for my conditions.
and since it's now sent to Atos,I'll have to send such letter to them if I want.
I think it's too late at this point and I have to attend the assessment.