How to remove a voicemail notification icon that won't delete?

[BarbaraPickle]

I have that tiny voicemail icon on the top left of my phone. Despite having deleted the voicemail & having no new voicemails, the icon persists & won't be removed. The 'block notifications & clear' underneath are shaded so you can't click on them. I've been through the storage & apps parts of my phone & emptied caches etc but nothing makes any difference. Any ideas? I really don't want to do a factory reset.

Umm might be obvious but tried:
-software update
-turning phone on and off again

Tried both of those

i find that you have to save and delete the voicemail i think on an iphone you press either number 2 or 3 on the keypad but you have to do it at least twice

I've no idea what's happening but it finally disappeared! Result - until next time...