iOS 26 and FaceTime Audio

I hoping I can get some help/advice and/or provide some for anyone experiencing something similar.

I have several contacts setup in my 'favourites' list in the phone app whom I call using FaceTime Audio. I've set them up historically by adding their name, selecting 'call', then selecting FaceTime audio attached to their number (not email). They've been on my favourites list for years and I've changed nothing as to how they are set up or how I call them--successfuly using FT audio in this way.

I have preferred using FT audio to WhatsApp as most of my close friends and family have iPhones and I like the ease of it etc etc.

These particular contacts are 'international' contacts and thus FaceTime Audio is necessary to call them.

up until the recent iOS 26 update, this has always worked as it should.

Well I just got hit with a £545 bill from EE as it seems that recently (since the iOS 26 update) those FT audio calls have been made as REGULAR INTERNATIONAL cellular calls.

I had thought something was odd before I received said bill, because each time I called one of them from my 'favourites' list(as per normal), I would get a popup message saying "Use Mobile Data To Call (person)" (person) cannot accept FaceTime audio calls. Then 'big blue button'-- "Call (person)".

I thought the header which says "USE MOBILE DATA TO CALL" was just something new in the ios26 letting me know that the ensuing FT audio call would use data(obviously), that I should 'be aware' of data limits, etc. I DIDN'T THINK THE WORDING MEANT I WAS MAKING AN INTERNATIONAL CALL using traditional cellular means, with hefty fees etc.

I rang EE and they were unable to reverse charges/offer refund as the calls were made on my end blah blah blah...

I then go and randomly click on the FaceTime icon on my phone (which I never use as I only use FaceTime audio with the people aforementioned which have been in my favourites list for years), and like lots of apple apps when you click on them the first time after updating the iOS software-- it says something like "welcome to (app), setting up FaceTime...."

The 'setting up Facetime' caught me off guard.

This leaves me to think that FaceTime was deactivated in the update process (unbeknownst to me). Could that be? I also can't help thinking that the wording of "USE MOBILE DATA TO CALL" implies I was using data to make the calls, not the cellular service.

Could Apple be at fault for this and might I be able to somehow be compensated?

Not a massively big deal, but I don't consider myself anything close to a tech idiot, and honestly feel quite ****** off that I had to 'open' the FaceTime app for "FaceTime audio" to work in the way it's always worked for me in all previous versions of iOS(i.e. associated with the contact-- not made via the app itself).

This cost me a lot and I hope no one else goes through it.

anyway, if anyone has any helpful thoughts/advice I would appreciate it.