whats my next step for collecting payment if I'm passed 120 days from completing a job
I am sorry for the issues. You will need to file a lawsuit. The limit for AZ justice courts is for cases up to $10,000.
If you want to proceed to do this yourself, you can find general information and forms here https://www.azcourts.gov/selfservicecenter. This is for Maricopa county http://justicecourts.maricopa.gov/CaseTypes/civilsuits.aspx. For other counties, review the court website for any forms and information. For fee waivers, review this https://www.azcourts.gov/courtfilingfees.
Nolo has good articles and books that may help you prepare https://www.nolo.com/legal-encyclopedia/representing-yourself. You can search for cases here https://scholar.google.com/. Arizona rules of procedure are here https://bit.ly/2Nfj5kx.
You may qualify for free or reduced legal services so apply and see if they can assist https://azcourthelp.org/home/legal-aid-resources.
If you cannot afford an attorney under a full representation or you prefer to do this yourself but with the opportunity to get legal advice as needed, along the lines of a coach in some ways, you should consider hiring an attorney as needed under a limited representation. This provides a general overview and some Q&As on this type of representation https://bit.ly/2RaeHEP. Our office and others offer these services so reach out and see if this option makes sense for you and this matter.
I hope it works out and I wish you all the best.