Remove/Delete old, inaccessible sync device from account.

Question

Hello, I am a bit of a tinkerer and a tech junkie. However, I still find sync to be a very useful and handy tool, and have it applied to all of my devices (tablets, phone, multiple computers). Due to my never-ending quest to make things better, though, I am frequently changing OS'es and uninstalling apps/rearranging registries on many of these devices, so I often find myself needing to reinstall firefox (and thus re-sync).
The only problem here is that sync recognizes each new iteration as its own separate device, even though a vast majority of them cease to exist entirely and are gone forever. This makes my "Tabs From Other Devices" page a huge pain to access, as most of the device names are the same and a lot still have active pages in them.
How would I go about deleting these old accounts from my sync account? Changing my password does no good at all, as since the devices cannot access the server any longer they are still present in my database, and as such are still annoying. Any help is appreciated!
Two pictures of the problem is as follows. As you can see, there are many apparent duplicate devices:
http://imageshack.com/a/img14/5290/a29b.png
http://imageshack.com/a/img59/6697/6sp4.png

Answer 1

I have tagged the question as escalate. That may result in HelpDesk or someone knowledgeable about Sync providing an answer, but that may take a few days.