Welcome to Vodafone Community
A PUK is only needed if a person has activated the sim pin in their phones settings and then have inputted the sim pin in wrongly too many times.
What I've seen from previous posts is that for some reason a phone is asking for the PUK when a person is trying to use a NUC to complete the unlock of the phone so it accepts any Network Sim cards.
This sometimes happens with Samsung phones. Some Samsung Phones actually need an unfreeze code aka the mastercode to which customer service on 191 or Live Chat can help you with.
A person also needs to use an activated alternative sim card i.e. connects to mobile data etc.
I hope all goes ok for you.
Current Phone > Samsung Note 9 _512Gb > Model: SM-N960 Hybrid-Duos.
Samsung One Ui / Pie.
Samsung Gear s3 Frontier Watch.
When i insert a different network sim, it says the SIM network is blocked please enter puk code, but no code that I have been given wether it be from Vodafone or the new sim provider, none of these work, every code I enter just says unsuccessful everytime, literally no one can give me the right code