I have been an O2 mobile customer from back when it was BTCellnet and still have the same number. I use my phone probably only once per month on average. You can therefore understand why I am a Classic PAYG customer.
I have not been aware that O2 were stopping the Classic tariff for new customers. There has been no communication from O2, but I recently found out online, and I tried to log in to my O2 account. I could not sign in, but set up for a code to be sent to my phone in order to reset my password etc. It did not work! The website told me there was no account with my number! (Maybe why I have not had an email from O2?)
To cut a long story short, I have re-registered and now have access - although it shows my device as one I had upgraded from 2 years ago. Ho-Hum! I am not sure what has been going on at O2 for my account to have disappeared as my phone is still active with plenty of credit. Anyway, I hope this is of interest to others.
Regarding the Classic tariff today, I notice the web-site now indicates the need to top-up or add a bolt-on every 6 months or the phone will be disconnected. Yet the link on the same page to the Classic Terms and Conditions does not refer to that requirement. I understood I just need to use the phone for a chargeable event every 6-months. I have looked at others posts here but none refers to this new requirement for topping up or adding a bolt on every 6 months.
For now, my phone remains active so hope that continues
Just a chargeable call every 6 months is all that is needed @Bonkers