In the app
Open You › Privacy & Data › Delete my account. This deletes your account, its cloud backup, and all Bandhan data on that phone, immediately.
Without the app
Email khanejas@gmail.com from the address you signed up with, with the subject "Delete my Bandhan account". We delete the account and its backup within 7 days and reply to confirm.
What is deleted
Your account and your cloud backup (groups, tags, notes, follow-ups, schedules, message history). Nothing is kept.