Welcome to Vodafone Community
Contact customer services via Live Chat or the numbers in contact-us or the Vodafone Social Media Teams via Contact-us-for-account-specific-queries. and they'll block your lost sim and send you a new one out.
When they send you the new one it may not work because of the account block so contact them again to have the block removed @ra7878
If you lost your phone as well they'll be able to block the phones imei as long as the phones been used on the Vodafone network
Current Phone > Samsung Note 10+ 5G _256Gb > Model: SM-N976B.
Samsung One Ui 2.1 / Android 10.
Samsung Gear s3 Frontier Watch.
Samsung Galaxy Buds.
@ra7878 If you are just wanting a PAYG SIM and the number is not important to you, follow this link: How do I order a free Pay as you go SIM? or a Vodafone Store will have supply of PAYG SIMs. You only need to cancel the previous SIM if there was a lot of credit. If you transfer the number to the new SIM any credit on the lost SIM will also move to the new SIM.