Welcome to Vodafone Community
Yes a person can unlock their phone as long as they meet the criteria to do so.
ie they use the Vodafone Payg Sim Card in the phone for 30 days making calls , sending texts and using data.
And then request the unlock.via this form > unlock-code-request form.
Some further help in unlocking-your-phone/how-do-I-use-my-nuc.
Current Phone > Samsung Note 9 _512Gb > Model: SM-N960 Hybrid-Duos.
Samsung One Ui / Pie.
Samsung Gear s3 Frontier Watch.