DB RegioRad Stuttgart bicycle huge problem

Hello everyone! Yesterday I rented a DB RegioRad Bike to get around Stuttgart and planned to use it the whole day.

When I got to my destination I paused the ride by following the instructions provided by the app, because I didn't want to leave it unlocked until I needed to ride it again. Fast forward 3 hours and I want to get back on the bike.

The bike is asking for an 'unlock code' that the app doesn't provide. It's not written on the bike itself nor in the app. The app didn't register the pause either. I couldn't unlock it and left it there (~500m from tje nearest parking station)

I cannot end the ride. I cannot unpause it from the app. The app is still counting the rental, it's already past 30 hours.

I've written several emails to info@callabike.de and unfortunately got no response except the automated ones that tell me a ticket number

I do not know what to do. It's such a frustrating thing for me. I don't want them to bill me hundreds of euros thinking I've stolen the bike or something.

Has anyone else experienced this? Any help would be greatly appreciated.