Thank you for your response.
Without a written agreement stating otherwise, your right to a commission depends on the completion of the sale between Company A and the customer. Here, you have extended the offer of Company A to the customer, but Company A has backed out before the deal has been completed.
Thus, here the only company that may have any legal remedy is the customer, if the customer accepted the quote from Company A. Because you are a sales agent, you are not a third party beneficiary
and thus have no rights to assert a breach of contract
. Thus, your rights are not triggered here because you only become legally entitled to the commission if the transaction is completed.
One possibility that might exist for you is that the original commission contract may still be in effect. Contracts often contain language that says they will bind a party's "successor" in interest. If there is such language and there is no document which cancels the agreement, and the agreement has not terminated by its own terms because of the length of time, then it would still be enforceable. If that is so, then you could bring a claim for breach of the commission agreement in that Company A had a duty to you to act in good faith.
In order to make this determination, I would need to inspect the commission agreement. Do you have access to it?