Hi - I too am having the same issue with calls going straight to voicemail. I am unable to deactivate the call forwarding. The message I get is "Faied to read data. Unable to deactivate call diverting when busy. Unsupported by operator". 

Hi ​@Tortielicious,

We’ll shortly send you a Private Message to your Community account so we can discuss your issue further.

To access your messages, click your profile picture in the top right hand corner and then click ‘Private Messages’.

Alternatively, if you are currently logged in, you can use the following link: https://community.idmobile.co.uk/inbox/overview

We’ll see you there.

Kashif

I’m having the same issue and I’ve been told, via Live Chat, that I can’t accept calls from 01, 02, 03 numbers as not included in my plan?!  It’s an intermittent problem but as I’m a POA for elderly relative in hospital I need to be in contact at all times!  It’s happening when mobile is not in use, goes straight to voicemail but number doesn’t show on list of recent calls.  I can’t deactivate call forwarding, getting the ‘data can’t be read etc’  message which I’ve read can mean an issue with the SIM?  Will look at suggestions made but can anyone else help as I’m about to find another provide and to hell with the fees I’m expected to get out of my contract!