Calls blocked unless from a favourite contact

I'm on EE - the last couple of weeks I have been receiving text messages saying I missed a call but the phone isn't ringing and the missed calls are not in the Call History.

I googled it a bit and tested with my husband - When he is marked as a favourite in my contacts I get his calls, when he's not a favourite it goes straight to voicemail and isn't in the call history.

My 'Do Not Disturb' is switched off and the setting changed to allow calls from anyone when DND is on and restarted my phone but nothing has changed.  

Can anyone help please?