Same problem here. For the first 2 days or so I was getting around 1.2MB/s, now I am uploading at around 100KB/s.
I contacted by email and in chat, they asked for a bug report which I sent, and then asked me to restart and run as admin, with no change of course. They said the technical team will get back to me but so far no change.
This is utterly ridiculous. I will definitely look for alternative solutions if I am not given a decent reply as to whats happening and the problem fixed soon.
It has taken days to upload a couple dozen GBs!!
Ticket #ID954723504