Hi I've tried to activate my voicemail using *004*003538351234567#. 

When I do this I get a message saying "Call Forwarding Registration was successful"

If I try to check the status using *#004# I get a message saying "Call Forwarding Connection problem or invalid MMI code" and my voicemail does not seem to kick in. 

I requested a new sim to see if it would help but I am still having this issue. 

Can anybody suggest a fix?

Thanks