Joeri Transactions between banks are very complex, because of the great number of different systems banks use. Therefore it can happen that a payment that's usually instant gets sent as a regular SEPA transfer. It can also happen that a payment gets stuck, then a bank employee needs to search for the payment and release it manually.
You mentioned contacting support, but it should be Revolut support. Once a payment has left bunq, there's nothing else bunq can do. The receiving bank, Revolut in this case, needs to investigate the payment.
Duni can export a single transaction statement from the bunq app and send it to another bank, so they have the info they need. In case Revolut asks for a transaction ID, you need to contact bunq support, since you can't see this ID in the bunq app yourself.
