I regularly switch between sim cards on my iPhone 5 as I live abroad, usually I have no trouble inserting my nano Virgin sim. However in the past few days having come back to the UK I tried the nano sim in my iPhone and it just says No Service. I have switched the phone off and on, updated the software etc. The sim card works fine in my old Nokia handset. I don't know what the problem is.
No I have always used this phone with this sim card, when I first bought it a few years ago I used the virgin sim straight away and only 2 years ago started using a different sim card when I'm abroad. I last used it with the Virgin sim in April in the UK and it worked fine then.
I would check if the iPhone's 3G modes are enabled? Might it be switched to to 4G/LTE only? Despite the fact that EE's network is 4G enabled and Virgin Mobile is an overlay on EE's network, VM UK does not support 4G. If your handset is set as 4G only it won't see Virgin. That said I don't handily know where those settings are in your IOS as I don't have an iPhone handy at the moment.
Welcome to the Community, I'm sorry to learn about the problems you're experiencing with your mobile service at the moment.
You've mentioned the sim works in your Nokia, have you tested that recently? Just so we can rule out the sim as a potential issue. If so, would you be able to test another sim card in your iPhone, to double check the hardware in the phone is working as it should?