How to open this cover?

Our kid broke the dispenser thingy, apparently the axel that actuates the mechanism. The piece is apparently not available anymore and the service repair from Siemens didn’t even help me asssess custom repairability.

So, could anyone help me opening this baby? The model is KAD90L.

There’s one screw underneath the cover but nothing seems to move after unscrewing it.

Any help appreciated :)