Do you need to be registered for joint colors to work?

Yes. It's attached to your registration key, to verify if said joints are yours, so, yes... You do.

dammit, so I bought them for nothing?

hampa disabled my key because other people were using it somehow which pisses me off and the thing hasn't been resolved yet.

Yep, I suggest cutting your losses, and re-selling them in the trade centre, for as close to as much as you bought them for.