Welcome to Vodafone Community
Sorry to hear your number is not working.
Some instances why a number would stop working are …
A person is on a Vodafone UK Payg account and haven't used the number by making a call or text or use data or top up in any 180 day period. If this is the case then the number is permanently lost unfortunately.
A bill hasn't been paid on Pay Monthly so services inbound and outbound have been restricted.
The Vodafone masts are at issue which can be checked via Status-checker.
Vodafone have a help thread with included template here Network-issues-initial-checks-and-template.
Your phone may have failed so as a process of elimination try your sim card in another phone and then see what happens.
Your sim card has failed which may need replacing via a Sim Swap after contacting Vodafone Customer services to have a new one sent to you.
However as this is an open forum I would suggest to edit your post to remove your mobile number ( flagged )
Also there is no account assistance via this forum.
Please call customer services on 191 from a working Vodafone phone or call 0333 3040191 or use Live Chat.
The Social Media Team's can help if you contact them via Contact-us-for-account-specific-queries.
I wish you all the best with this.
Current Phone > Samsung Note 20 Ultra 5G - SM9860 Snapdragon.
Samsung One Ui 3.1 / Android 11.