I come here quite frustrated and I hope that someone can learn from this if they are thinking about upgrading.
I have kept upgraded over the years from Photoshop 6 > CS2 Standard > CS3 Design Premium > CS5.5 Design Premium and I recently decided to purchase CS6 Design & Web Premium.
When the time came to eneter the serial numbers on my new CS6 the CS5.5 serial was not accepted.
Several phone calls later and it transpires that when I purchased the CS5.5 upgrade, I was placed onto a TLP license (all my others were retail) and that this means I couldn't use my CS6 that I had purchased.
I made several requests to swicth back, but was told all I could do was return the software for a full refund - keeping me on CS6.
I could of course upgrade via the TLP but this has zero benefits and several drawbacks so I am reluctant.
1) It means you cannot buy retail any more
2) It really reduces the resale price (quite important as I am considering the cloud)
3) Rules out buying second hand or whilst working overseas.
The main issue is that I was never told that my licensing was being switched, and even if it was mentioned and I somehow missed that, the drawbacks were never explained - so I feel missled.
I have been told several times since, that whilst you can transfer from retail to TLP you can't transfer back. But I have heard no logical reason for this one-way-stance.
Sorry to hear about your difficulties... AFAIK you can still fully transfer Adobe software licenses that were purchased through TLP - and either way it was a digital purchase when you bought CS5.5.
So since you were able to get a refund for the CS6 upgrade, one possibility would be to sell your CS5.5 license and then sign up for the Creative Cloud, if that's been your intent. Or, you could keep it as a backup in case you stop your membership.