Depending on the amount owed, small claims court can be the next step. An attorney isn’t really needed there. No matter what, though, heading to court is a stress-producing hassle with no guarantee of a reasonable outcome.
There are also collection agencies that can be used in some instances.
The real goal, though, is to use whatever precautions it takes to avoid resorting to either of these last-ditch measures. For what it’s worth, I haven’t been stiffed on a job in, probably 25 years. Then again, I do background research on all new clients (it’s not hard), require deposits from most new clients and turn down jobs that strike me as iffy.
One thing to keep in mind is that successful companies that have been in business for awhile, didn’t usually achieve their success and longevity by cheating their vendors and contractors. And a quick web search will usually identify those that have. For a wannabe rap musician without references and a solid credit history, well, that just might be one I’d turn down in a heartbeat. At the very least, I’d require a deposit and payment in full before delivering the final product.