UNEXPECTED PIP PHONE CALL

Hello
Just to update you the lady never called back.
Today I received the dreaded white letter from Dwp.
Thankfully my award continues with no change for 7 years l, enhanced on both parts.
I didn’t send in any new medical documentation or letters from the dr or anyone else.
I just filled the form in pretty much word for word like the previous one 7 years ago as there was no change.
Actually, things have got worse but I don’t include them as was already on enhanced for both parts.
They didn’t write, or call or txt to ask for more evidence.
Letter just arrived.
Still to this day have no idea who that lady was!!
She did say she was from PIP then when I returned the call it said welcome to universal credit helpline?!
So hope this helps someone.
Thanks