Storage quota floor lower than stated

I have a free account at the moment and when I go to load a file of 150 kB, with still 2.2 MB of free space, it says that I have already used all my storage space. Why is that? I tried with both Firefox and Chrome and I cleared the cache but I still have the same issue.  I know how to free space and  I am able to do that, if I free 1 MB I am able to add stuff again. It looks like the storage quota floor is 97 MB instead of 100 MB. Is it a known issue? Is there a way to use all the  space?

Hi Adri G.,  The bug report forum is primarily for users helping users. I don't think there is much here that a user can do to help, so I suggest contacting the Devs via the Help Center . 

I suspect that at some point during the processing of your upload your quota is exceeded and processing stops. You should use the Help Center to get Roll20 staff attention and a ticket to track your issue. 

Thank you both for your replies. I'll use the Help Center then, in the meanwhile if anyone happens to know how to face this issue please let me know.