Friends using Vodafone network are unable to call me

[CS59]

I ported my number over from Vodafone 5 years ago. However, a few months ago i was made aware that friends calling from a vodafone number get directed straight to a vodafone voicemail, the call does not come through to me at all. I have checked this with many different phones on the vodafone network. 

O2 cannot seem to fix the problem and the last person i spoke to told me to contact Vodafone, which i struggle to understand as it is O2 that i pay every month....... However, i did this and Vodafone cannot identify the problem either and have no record of the number previously used with them.

Any ideas what the problem is or what can be done? 

[madasaf1sh]

@CS59 

Sounds like something has fallen off on the Vodafone end, as although your number is with o2, Vodafone still technically own the number, and they have to basically put a forward on and it sounds like this is now forwarding externally rather than to o2

You need to persuade /persevere with o2 to liase with Vodafone to fix the issue...  As unfortunately the only people who can fix it is Vodafone..