Bastiaan does this mean at any give point I can only have one open ticket?
I came here to ask the same: neither iOS nor android ever showed me a "new ticket" icon.
However, since I joined (March 2020) I have always been greeted by the app with the support screen with some boilerplate "hey, I think your app crashed lately, do you need help, here are <links>" text.
There was no (obvious) way to dismiss these, and nothing else on that screen, despite me trying to scroll.
Now I needed support (CC data must have been stolen somewhere, got fraudulent transactions in quick succession) the only way I found to contact bunq was by clicking "reply" on the boilerplate "greeting" text. And then it didn't let me choose an issue category but seems to have dropped me in the "misc" inbox.