Ok, thanks everybody for your replies. I’ve just alerted my bank and I seem to be safe.
Just to recap: I was in my usual coffee shop, using their WiFi. They presented me with their card reader, price on screen. I double clicked my iPhone home button, Wallet opens, I put my thumb on the button, complete random screen comes up (on Wallet, I hadn’t touched anything!): “your account has been suspended, blahblahblah (I think something along the lines of you need to reactivate it)”.
How did I end up in Safari? I can’t remember the exact step. I’m quite certain it wasn’t a link, I think I put my finger on the screen and presto: a form that asks me for my name, address (I think phone number too).
I filled that in (I had no cash Or card on me and the coffee was made), thinking that’d sort out the problem. But another form appears, asking for my card numbers and security code! I stopped there.
PS. It’s my local family owned coffee shop, that said “ the coffee is on us, loyalty scheme, get one coffee free every one hundred, 😹“.
PSS. As I said, there is no clear link between Wallet and this people, and the last thing I expected was for the app to serve me up with this rigmarole. So I won’t be using it again. If you gays can think of any way of taking this up with Wallet that doesn’t waste me another hour of my life I’d be happy to find out more. In any case thanks for your tips.