Using My Phone in the Isle of Man (a happy ending)
I use a PAYG T-Mobile sim card in my android Samsung Galaxy phone and I'm visiting Port Erin in the Isle of Man.
My phone didn't automatically connect when I arrived and I had to go Settings -> More Settings -> Mobile networks -> Network operators to see that there are two networks available: Manx Telecom Mobile and Sure.
When I selected Manx Telecom Mobile I received the message 'your sim card does not allow a connection to this network' but when I tried Sure my phone was able to connect.
I was able to send and receive sms texts but although I was able to make local calls, when I tried to make a phone call to the UK a voice said 'this number is barred on your phone'. I was also unable to use data to connect to the internet and this was true of my Osprey using an EE sim card.
Moderately soon after this, I received a text saying
'Welcome to Guernsey' <sic> and later on saying 'For Customer Services call +447953966150'
so I phoned that number, used the menu to ask for technical support and immediately spoke to someone named 'Jodie EE' or something like that. He asked a couple of sensible questions 'can you receive calls' and 'have you turned your phone off and back on again since you arrived'. I should have thought of trying the latter, it's so often true that flushing any cached settings cures a problem. He said he would do a network reset and this will take 10 minutes to go through so I should turn my phone off and back on again after ten minutes.
I tried this and, lo and behold, I was able to connect my Osprey* without fiddling with the internal settings, connect to the internet on my phone, and make phone calls to the UK. Jodie phoned me back to check that it had worked and I was able to tell him that everything is hunky-dory and I'm a happy bunny.
Excellent service from the EE/T-Mobile help desk, thank you.
PS. If you are phoning 01234 567890 from the Isle of Man you must use 441234 567890. If you try 01234 567890 then it will dial, briefly ring, and then disconnect almost immediately.
PPS The next day, after I had enabled wifi and connected to my hotel I wasn't able to revert to data until I rebooted the phone again.