Help me to deactivate/disable voicemail on my phone or 3 number.

[Olu]

Please assist to deactivate/disable the voicemail on my phone or 3 number.

Thank you.

[thelinefinish]

Try this (from the website of a mvno who piggyback off Three):

To turn off voicemail

Dial ##002# or ##004#

To turn it back on

Dial 00407782333123# or *004#

[Paddiewack]

I have to say I just got an error message when trying this. But then perhaps I’m doing something wrong. 

[thelinefinish]

Oh dear, many apologies. That's strange that it works for a Three mvno but not Three themselves.

[Paddiewack]

No apologies required. I tried it in a rush and I’ll try it again tonight at home. 
Thanks for posting. 

[Paddiewack]

You need to contact customer service either via live chat or by calling 333 depending on whether you’re payg or contract. They will do it for you. As far as I’m aware there is no other way.