@cherrysthename
It was....to book for me in for a smear test. God I feel like such a (relieved) idiot. Usually they would just text.
I've been having health problems going back to over a year which haven't been resolved yet (hence still waiting on referral app). I wasn't a wimp before any of this.
Why did they not say this then?
YANBU!
This really REALLY pisses me off to the nth degree. When someone leaves a message saying 'call us when you get this message' with NO CLUE what it's about. It's almost always at 4.57pm on a fucking Friday too, so by the time you see the message, it's too late to do anything about it, and you dwell on it all weekend.
I had an important hospital appointment some 3 years ago, on the Tuesday after Easter at 3pm, and at 4.45pm on the Thursday before, (FIFTEEN MINUTES before their office closed for 4 days for Easter,) someone rang and left a message on my mobile phone, and said 'can you call us when you get this message please?' No clue what it was about or anything.
I couldn't get back in touch til the Tuesday morning - FOUR days later, and I worried and fretted and panicked for the entire 4 day Easter break, and it ruined the whole 4 days. I thought 'is my appointment cancelled? Is it being altered? Has it changed to Tuesday morning, and I will miss it because it's 9.30am and I won't be able to get through in time? 
It may sound dramatic to some, but it's just how I am (and how others are according to this thread.)
What did she want? To tell me the appointment time had changed from 3pm to 3.15pm.
Why the FUCK could she not have said that on the voicemail message? 'Hello Mrs Frosty, just a quick message to let you know your appointment time has changed from 3pm to 3.15pm on Tuesday...' That's ALL she had to say. Would have saved me a LOT of fretting and stress, and would not have ruined my Easter break. 
Similarly, the school always used to send us letters (often stroppy ones) and they'd arrive on a Saturday morning, so we couldn't sort anything out til the Monday! And one time, we booked a week off for our 2 daughters in early December to go to Switzerland. We booked it in MAY.
We had always booked time out of school (one week) since they started school at 5 (they were 15 and 16 when we went to Switzerland,) and there had been no issues. Not at the 4 years at secondary school - OR the 6 years they were at infants and juniors. And it NEVER affected their studies.
First day of the school summer holiday TWO and a half months after we put the request in, we got an arsey letter from the school REFUSING the fucking week off in December!
After allowing a week in school time for the first 4 years they had been at the school, they changed the rules.
And they chose to wait until the day before the school closed for summer to send the snotty letter, so we didn't get it til the school was closed! We were livid. Two and a half months they'd had to send the refusal letter.
I wrote them such a snotty letter, and said how disgusted I was that they had done this, and we will absolutely still be going, and taking the girls. We heard nothing back from them, and they said nothing about them going, and we got no fine or anything, but they did get 5 days 'unauthorised absence...^ 
I was glad when they left that school. It was when it changed to Academy status that it went to shit. Refusing a single day off, sending the kids home for having the 'wrong' shoes on, and keeping them in for detention (for something as innocuous as talking in class,) without telling the parents, so the parents would be waiting outside for them, not knowing where they were. Awful !
By the way @cherrysthename ignore the naysayers on here, and the people lambasting you (with sarcastic comments like 'just how DARE the NHS try and save your life???' Typical comments from some mumsnetters. Ignore them. They'd have been just as pissed off with a voicemail message leaving no clue as to what they wanted. YES they really would! 