Can't change voicemail number or remove notification

[El Nombre]

My mum just got the A3 but she's having some issues with voicemail. Firstly it won't let her change the voicemail number. From what it sounds like, because it's actually a contract phone, it refuses to recognise anything other than the original O2 settings. She's actually running Giffgaff which uses the O2 network. Easy workaround is to just dial the number in her contacts but it'd be nice if the notification linked straight to the correct number. Does anyone know if its possible to change it? It just says unsuccessful when doing it by the normal method.

Secondly, the voicemail icon refuses to disappear even after listening to the message. I guess this is probably something to do with the first problem as it's using a different number but you can't even swipe the notification away.

Both these issues seem to be fairly common with Samsung phones from doing a bit of hunting but most of the discussion i've found is all a few years old so was wondering whether anyone had found a solution since.

 

[Rukbat]

Voicemail is a different set of hardware and software for each carrier. I'd bring the phone into a Giffgaff company store, ask to speak to a technician, and ask him/her to please get the VM set up properly, both on the server and in the phone. (Some settings that you may need changed are things you don't have access to - but they would.)

 

[El Nombre]

Giffgaff don't have shops, they work using help from other customers but i think they might have a phone number for issues the community can't solve so could give that a go. I feel like this is more a Samsung or O2 issue though.