I had previously paired my accounts, but my files are no longer in my personal Dropbox.

Help...
I've had a personal paid plus dropbox account for 3+ years for all my freelance design work. A 6 months ago I was working for a studio that also used dropbox and gave me a work email to access their dropbox from my laptop as well. I could then access their files and my own dropbox. I remember I could access both logins from the dropbox module icon.

I brought a new laptop and began syncing my dropbox onto it and noticed that I've just logged into their work account and my personal account isn't there. Therefore all my personal dropbox files are now on their work account and when I went to login into my personal account it's created a brand new dropbox account and is completely empty.

So there's a few questions I have..
1. How do I get all my files back onto my personal dropbox?
2. Why has my personal dropbox account disappeared? 
3. Why have I been paying getting billed for PLUS on my personal dropbox for 6+ months while the account hasn't existed?

Any help would be appreciated, thanks!