Are Debt Relief Companies on the Level?

Need help on story for Experian on the ways debt relief companies can scam customers into buying services they don’t need and other possible “under the radar” bad/unnecessary moves debt relief customers might make. What are the biggest DR scams and why? What can customers do to avoid them or extricate themselves out of bogus services, fees and charges, etc.? Are debt relief companies worthwhile in the first place? Why or why not? All comments welcome. Requirements: Debt experts, money experts, debt relief providers, credit management experts, financial planners