Welcome to Vodafone Community
I assume you want to Unlock your phone so any network sim card works in it.
Please ensure the other Network Sim Card your using is activated.
i.e it connects to mobile data etc.
So if Vodafone have supplied the Nuc to you already then try putting a 0 before the number.
If this does not work then you may need a mastercode as well as the Nuc.
This is a thread with some of these mastercodes in > Master-codes.
If they do not work then if you call 191 or use Live Chat they can ask their Nuc Department to supply you one and or you could try asking Samsung Customer services for the mastercodes although they can't help with unlocking the phone.
I wish you all the best with this situation.
Current Phone > Samsung Note 10+ 5G _256Gb > Model: SM-N976B.
Samsung One Ui 2.0 / Android 10.
Samsung Gear s3 Frontier Watch.