Missing voicemails

[thomasS_2642143]

I have a sim only deal, and used to get a text and voicemail ok but now when someone leaves an voicemail (Ive tested) and I call to retrieve it the automated voice says ‘you have no new messages’. 
I am missing important calls as a result. 

any clues about how to fix?

[Chalkychap]

Perhaps speak to SMARTY support via their web chat service, @thomasS_2642143. 

The advisers work between 8am - 8pm daily.