Then you might have some problems. Hmm... Let me check with friends and see if they have any solutions. @Jozocircle and MrThomsn (My friends on TS) said that /p list would tell you which plots you're allowed to build on, which gives the coords to plots.
Looks like you'll have to start over. If there are no plots you can even build on. What is the message when you enter /p h? Also, what did you do before you lost your plot that might have made you lose it?