Telephone calls from DWP

A DLA claimant got a telephone call from the DWP DM about her DLA claim.
Nothing unusual.
However, she has both mental and physical disabilities.
She became extremely anxious and told the DM how she was feeling, she wanted to end the call and referred him to the claim form.
He insisted on continuing the call and asked her questions about her various needs.
She didnt think she had given adequate responses.
She was also ill the whole weekend as a result of the call.

Of course I’ve written complaining, and should the call be influential in the decision, I will wish to argue that it should not be given weight in the light of the circs.

I cant seem to find any guidance on phone calls protocol or when a claimant indicates the call is detrimental to her health.

Anyone cast any light?