Unable to reset the greeting in my iphone 11

I’m currently on a iphone 11 and I had changed my greetings a week ago as a joke to prank my friend

It was to make him think i picked up the phone but it was really my voicemail, so I went to greeting and set it all up but when i went to change it back to the default it said it was already on the default and that i couldn’t save jt

The only way I could save it was if I made another custom greeting but my greeting didn’t change and when i saved and went back in it just went back to default again even

I even called on multiple other phones and it’s still the voicemail i made a few weeks ago

[Re-Titled by Moderator]