Voice mails

[JB50]

I have two issues since signing up with O2. The first one is that I can’t retrieve My voicemails unless I turn my mobile data on the second issue is when people are calling me it’s saying my phone is engaged when it isn’t my partner called me while I stood next to him and it gave the engage tone when the phone

[pgn]

All voicemail tips here, @JB50 - Guide: All you need to know about O2 Voicemail 901 

And your mobile data, unless you have a poor mast signal, should not impact accessing voicemail if it is set up correctly.

The engaged bit sounds like you need a quick read of Guide: How can I sort out my network issues? 

Your SIM might also be playing up, try removing it and carefully wiping it with a lint-free cloth before replacing it in the phone and rebooting the phone.

Good luck, @JB50.