Log out from your Bigbangram for 1-2 days.
After 1-2 days go back to your Bigbangram account and click RELOGIN button
Go to your Instagram app and click "send security code" button.
Enter security code that was sent to your email or phone.
If you did all correctly you'll be able to login and continue the promotion.
If you still can't login then contact us on firstname.lastname@example.org
Customer support service by UserEcho