Legal Question in Real Estate Law in California

This isn't enough information. How far did they move it? Do you know why? What does your contract say, if anything? Is the spece enclosed or not? Were you up-to-date on the rent?

Without answers to these questions, I can only guess, but my guess is that what you have under your storage contract is a license, not a lease of a particular spot, and this would tend to give the storage operator a right to move the trailer within the confines of their storage facility.

If they moved it out of the facility, that would be improper unless you were delinquent on your rent or there were a serious emergency justifying its removal for safety reasons.

Simply moving a trailer from one unenclosed and unlocked parking space to another would be permissible except in the unlikely event your contract says they are leasing a particular space to you for your exclusive occupancy and use. Even then, a move for nonpayment of rent or a serious emergency might still be justifiable.