Questioning commission for buyer's broker

REThink Real Estate

Q: Are we liable to pay our broker the full commission if the seller is a builder who will pay only a $1,000 referral fee?

My boyfriend and I were looking for a home in California and decided to use an old acquaintance as our agent. Prior to signing a buyer’s agent agreement, we found a "new build" on our own while driving around the neighborhood, but the home we wanted wasn’t available at that time. We later went to view other homes with our agent and signed a buyer’s agent agreement, which was backdated.

The only proof we have of when we received the contract is a copy of the e-mail in which the contract was sent to us and a copy of the e-mail of when we sent the signed copy back to our agent.