PIP telephone review appointment- no call received.

I had been sent a letter with a telephone assessment for my review (I sent my form in 1 year ago) today.
Yesterday I got a courtesy call, confirming the appointment and the name of the assessor.
I waited half an hour over my appointment time today, then called IAS to say the assessor hadn’t rung me.
She said she had no idea why, there was nothing on the system and has made me another appointment for two weeks time.
Is that enough to prove it was not my fault the assessment did not take place, or should I follow it up with a letter to them confirming what happened?

I don’t really understand why I am having this assessment, about 3 months after I sent my form in I received a call out of the blue, the lady asked me some questions to clarify a few things, then said she would write the report and I would get a letter. I did get her name.
I never heard anymore.

In the meantime we had a family death and I couldn’t focus on anything.

Should I be contacting them now, to ask what’s going on?
Thanks.

A letter or phone call Gordon?

Thank you.