PIP APPOINTMENT

I am my son’s official appointee. In November 2018, I duly ensured we fulfilled our obligations & attended the PIP Consultation Centre arriving at approximately 10 mins prior to appointment time. The receptionist mentioned that she had telephoned. The telephone message was to confirm the appointment & to phone back if want to.
The receptionist at the desk then went on to mention that she was telephoning to cancel the appointment. I was rather puzzled at this as there was no indication at all in that telephone message of any cancellation. However, the receptionist stated that they were running late and when it gets to the appointment time they will take it from there. The waiting had approximately 2 – 3 persons waiting and were called through, I presume to the consultation rooms, shortly after.
The receptionist approached us numerous times in the waiting room, informing each time a longer wait. We were asked on each occasion to stay or book another appointment as there were a lot of pages (PIP form / extra information) that I had completed, I informed that the appointment had been scheduled weeks ago and that the DWP had these documents for months. The receptionist informed that they are not allowed to open them & that the ‘lad’ had just opened them to read. The receptionist said that the decision was ours to wait or book another appointment. I informed my son has been distressed over this appointment & to go through this again is putting him under unnecessary distress again. It was suggested that we could go to the door at some point to get some fresh air –my son did so & I suggested if I could go & come back with my son – I took my son for a short walk, my son was becoming inwardly upset & informed me he wanted to go home when we were outside – we went back to the waiting room.
I noted that some staff started to go home, including the receptionist, from then on, a gentleman took over at reception. The gentleman approached and informed effectively that it would be another over half & hour or longer & was again asked & given the choice of staying or rescheduling another appointment. I reiterated effectively that this appointment had put my son under distress & to be perfectly honest wanted my son to try & stick the waiting out. I informed the gentleman, given the choice of staying or another appointment that it was up to my son how he was feeling? My son could not manage any longer & clearly relieved to go home, opted to have another appointment. At that point were asked to go over to reception – I kindly reiterated & expressed that I was effectively disheartened as from my perspective had done all that was required from us, more importantly causing further unnecessary distress for my son re another appointment. Son has a diagnosis of a severe enduring Mental Illness. Such a scenario is nothing but a total disgrace
The gentleman informed that he did not want the assessor to miss anything due to being rushed & I fully agreed. I mentioned if a paper-based decision could be made due to this appointment not taking place & I was informed that this could be done. The gentleman informed that if there was enough evidence on the papers it could be done.
I informed I can attend certain dates December 2018 – he said the computer did not go as far as that (Cannot book that far ahead). The gentleman gave a date in early December 2018 – I informed I doubt I can very much manage that date – I asked if I can phone him back to let him know re that appointment - he said that I could & gave me a post note with his details stating names first name terms of whom to contact.
I telephone the assessment centre early the following week, I spoke to the receptionist I informed of the available dates in December – the receptionist said that she cannot book that far ahead but will put a note for the dates I can make it with my son 2018. I was asked for my telephone number
I received a PIP letter today. ‘YOUR NEW APPOINTMENT LETTER’. This letter dated 2018, the same day my son & I arrived for the appointment, that did not take place. The new appointment is for December 2018. This is the date I informed I could not accommodate.
I am also concerned that if assessors are not allowed to open the PIP papers that I sent in until the actual appointment – is it acceptable that they are opened well before a next appointment? I do feel that I / we have been messed about - am I wrong in thinking this?

Thank you for your reply - much appreciated.
Due to my son waiting for a further appointment & putting him through this (along with the difficulty I am having juggling work & caring) - will I be able to to request a paper based assessment? I am just concerned about the impact all this is having on my son's mental health.