PIP renewal phone call

Yesterday I received an unexpected phone call from a woman who said she was from PIP. She said she wanted me to go for my assessment the next day. She was very pushy. I said I wouldn’t be able to asni have a hospital appointment. She then said well what about the day after. I explained that I am currently on fast track with the hospital to investigate a possible cancer and they have asked me to keep the next couple of weeks free so they can fit in various tests/appointments at short notice.
She then said ok so I’ll give you an appointment in two weeks time then. I had to explain again that it won’t really work like that and the ‘two weeks’ wasnt a definite timescale and it depends what they find as to whether I would then be available. I had to keep mentioning the cancer investigations as she just wasn’t listening and was badgering me to book an appointment there and then. It caused me a lot of upset having to keep repeating the word ‘cancer ‘ especially as it’s all happened very suddenly.

In the end I asked whether she could just send a written appointment as normal and I would see what my situation was at the time as I just couldn’t commit to booking an appointment over the phone. She said that wasn’t her department and that someone else would have to deal with it. She said she was sorry for bothering me and hung up.

Is this normal? I’m wondering now if I’ve done something wrong in refusing to agree to a last minute appointment over the phone. But circumstances mean that I just can’t do that until these investigations are done and I have some results.

My current award doesn’t finish until December 2019 and they’ve had my forms since January. As much as I’d like to get the assessment out of the way, now isn’t the right time to do it.