Possible Clues:

• "Don't worry about it"
• 'You don't really have to'
• “Thanks, but it’s covered”
• 'Don't bother!'
• 'We're all set without that'
• “That’s unnecessary”
• "Thanks, it's already done"
• “Don’t bother”
• 'Thanks, it's already done'
• “Seriously, you don’t have to”