I missed confirming an increased direct debit and now it is cancelled after 5 days. How can I still execute that particular payment?
Wouter As Dennis already said, there is no way to re-do a missed direct debit after is has expired. After the confirmation period ends, bunq automatically refuses the payment, so the counterparty has to send you a new one.
The shop or merchant would need to send a new direct debit request to you. Once it has been cancelled it can't be paid anymore.