Maintenance of Update-Accelerator wont work

Good morning folks,
i have some problems with deleting old updates from the Update-Accelerator. In fact there are still .deb files from 2015 for instance.

When i try to delete them in the service menu by clicking “delete everything that has not been accessed for a week” or something like this nothing happens. At least i can not see anything changing. The used space stays at the same level. I would love to spread iOS updates from there to reduce my WAN trafficc a bit.

Can anyone confirm this?
What kind of logs or information do you need so we can debug this?