I don’t know what the details are with respect to timing, etc., but unless you received some sort of release from the brokerage, you’re going to need a lawyer to sort this out. Do you have anything from the agent as evidence that “all would be good” if you didn’t sell using anyone else during the 3 months following the end of the RLA?
The standard form in California was written by the realtors for the protection of the realtors. One should always be cautious . . .