No, there will be no re-granting of 1GB Welcome Gift if you have missed the 7 days redemption period.
MyDigi App Support
To check, please go to MyDigi app > Internet (Swipe left once on usage screen) and click on ‘View Details’ to view more info.
Validity expires 7 days after time of redemption.
No, you will not be able to receive the 1GB Welcome Gift again because you have registered your phone number with MyDigi.