Legal Question in Business Law in Arizona

This is an evidentiary problem before it is a business problem. You need to be able to prove up the existence of the agreement.

You have not provided enough facts to really answer your question. Oral contracts are enforceable under Arizona law. The party bringing suit has the burden to prove that there was a contract, that there was an offer, acceptance and consideration for the promises made. There are other ways to prove the existence of an agreement beside the testimony of the parties to the action. You should consult with legal counsel to determine if you actually have a contract and if you can prove that and what the terms of the agreement provided.

How much money/labor/equipment was involved in this agreement? Was there a substantial performance by one party with the other parties' awareness of the performance? Did the deal involve renting property or purchasing real estate? I really need more details.