A trailer was sold with a written contract and live in AZ It has been six months and they have failed to make all the payments as agreed What can you do legally to get the money or the trailer?

A trailer was sold with a written contract and live in AZ It has been six months and they have failed to make all the payments as agreed What can you do legally to get the money or the trailer?
I'm not familiar with the specific laws in Az related to this situation, but as in most states, you probably have to get a judgment against the party in small claims court (assuming the amount of the claim does not exceed the jurisdiction of small claims in your state). If the party has other assets, especially a second vehicle which equals or exceeds the value of the judgment, you can generally have the vehicle legally seized by a deputy. You probably can't seize their principal means of transportation. This will usually cause the party to make restitution for the return of their vehicle. You can also get a lien on the parties real property, but usually you will only see the money when they decide to sell the property.
I don't claim to be a legal expert, but I have gone through a similar predicament in the past.