Support ticket - where to open it?

Can anyone let me know how and where to open a support ticket?

I got issues with files that are not linking properly from MacBook to the online version.
- Files are still shown online even though I deleted something on MacBook.
- Sometimes I can not move files online to a different folder. 
- Files made available offline on my MacBook - getting the green tick (sync done) but then the PDF version I see online is not correct online. 
- Files like PDFs show online but have 0KB. Have to manually drag them to folder to make sure they show content. 
- Firewall turned off. 
- Got a popup window the other day saying "It looks like your connection to dl2.boxcloud.com is blocked. We think we can make file previews faster to you. To do that, please ask your network admin to configure firewall setting so that dl2.boxcloud.com is reachable." 

WHO CAN HELP WITH THIS?
Many thanks,
Marie

It is effecting work really badly! Need urgent help.