Storage usage of 'Services for Blackberryhub+'

Hi all,

hopefully someone can give me a tip for this problem: (image was here, but post get's marked as spam with any link)
'Service of Blackberry Hub+'
App Size: 52,76mb
User Data: 11,48GB
Cache: 143kb

The 'Services for Blackberry Hub+' use an insane amount of storage (currently at 11,48GB - highest was about 16GB).

Thinks I've tried:
- Delete all accounts on hub
- Deactivate/deinstall the hub (for that I had to revoke all permission, including device administrator, only then I could remove it)

Did the last thing about a week ago, and today it's again using all my storage (I have about 500mb left).

Accounts on my Hub:
- 2x Exchange (both without attachment save, and only go back about ~2 weeks)
- Whatsapp (not much media, mostly text)
- Slack (nearly never used)
- SMS/Telephone

Last resort would be to reset my phone, but I would rather not (adding 2FA apps again is a hassle).

Does anyone have any sort of tipp/can help? Please :-)

Thanks for your answer