IAS cancelled appointment +

Hello, my hubby's appointment for his PIP assessmnet was to be today. Yesterday at 9.30am I got a call from IAS (Independant Assessmnet Services , formerly ATOS) to say they had cancelled the appointment because the Health Professional/HP needs a chaperone. They changed it to Thursday 22nd. My husband has anxirty and mental health issues. My question is, if they had read the information given on my husband they shoudol have relised before now they needed a chaperone. He is not violent, but if stricken by a panic attack he will make a straight line to a safe place. If someone is in the way he may push passed. I explained this in his paperwork. I have rang and tried to make a complaint but the telephone operator even tho i explained everything to him would not put the words I used (no profanity). He said I had rang to complain they changed the appointment, that was it. I had to asked 3 times to be put thru to a supervisor before he expalined i would be called back in 48 hours. He said if i want to use my own words then I have to get a complaint pack. He said the superviser would call back. BY 4pm I rang and eventually got put thru to a manager. She apologised for the incorrect info I was given but the main issue is. I thought they had to give you at least a weeks notice for an appointment, even if they change it, I also think giving a person a few days notice is unfair. He has been in a state of panic since the appointment came thru and now he is upset too because he feels they are sending a body guard. I hope this makes sense, I have had no sleep but the odd hour since sat night and now having to wait longer for the appointment sleep is now in the distant futire probably Friday now because he will be like a wound spring Thursday. I thought they were not to cause severe psychological distress to clients?

Thank you. Do they have guidelines regarding how much mental trauma they are allowed to cause ?