Hi
I understand your getting the message but....,
Have you tried turning airplane mode on and off to try and to reset connection or On the iPhone hold down the Sleep/Wake Button and Home button together until the Apple Logo shows. Then On seeing this Apple Logo release both buttons ,and the iPhone will reset , which has been known to clear most glitches. Another option is Settings -> General -> Reset -> Reset Network Settings.
A sim swap typically takes 24 hours. I have had one that took two days.
Has Service stopped on your old sim at all ? If not it's likely failed which could be that the new sim is faulty or the networks busy.
It's a shame about your most local highstreet shop.
Please keep trying live chat or the dedicated customer service number from your phone 191.
Current Phone >
Samsung Galaxy s²⁵ Ultra 512gb.