Welcome to Vodafone Community
You should be able to tap on the forgot my username / password when going onto the online myvodafone @Jetheesan
These links may help.
Customer services on 191 or Live Chat or the Vodafone Social Media Team's via Contact-us-for-account-specific-queries would be able to help too.
Current Phone >
Samsung Z Fold³ 5G.
Previous Phone >
Samsung Note 20 Ultra 5G - SM9860.