Lately over the last few weeks I've noticed a few issues that are appearing.
I've tested this myself and what happens is even that my phone's on with a full battery and over 80% signal - it goes straight to my voicemail yet I can still ring out and when I do this calls come back through.
Also, SMS messages are not coming in as quick as well with 1 delivered on Sunday night which was sent to me on Saturday night by my housemate and the "missed call" texts have been appearing 24 hours later than expected.
Anyone else on O2 having these issues?