"No appointment, letter, or call"

On my sons initial appointment to see a community paediatrician at The Rainbow Centre in Burnley General Hospital, the specialist referred my son for an ADOS assessment with a Specialist speech & language therapist. They said my sons appointment will be within the next 6 weeks and if 6 weeks passed with no appointment I was told to call The Rainbow Centre back to ask for an update.

It has now been over 8 weeks and I have not had any correspondence from anyone, no appointment letter or call. 10 days ago I phoned The Rainbow Centre several times and nobody answered the phone, So on the last call I left a voicemail, on the voicemail message it says leave your details and we will call you back, I left my sons details our address and telephone number and explained what my call was about, and nobody has yet called me. very unprofessional, why have a voicemail stating you will be called back when they don't call you back. I am left waiting, unsure of what is happening and is not fair on my son as he requires this assessment asap as we have been waiting months for any progress, it was October last year when I took him to the Gp for Autism referral and since then we have only had one initial appointment.

I feel very hurt as I feel it's too long for my son to wait.