How do I handle a service provider who does poor work?

Document everything
Take photos and videos of poor work from multiple angles. Keep written notes with dates and specific issues. If you have a contract, note which clauses the work violates. Documentation supports your position if disputes escalate.
Communicate in writing
Don't rely on phone calls or in-person conversations. Email or text the provider describing the problem and requesting correction by a specific date. Written communication creates a record.
Reference the estimate and contract
Point out what was promised versus what was delivered. Quote the relevant contract sections. Stay factual and unemotional—"The cabinet doesn't close smoothly" is better than "This is garbage."
Request remediation
Give the provider a reasonable timeframe to fix the work. Most will respond to documented complaints. If they're responsive, schedule inspection of corrected work before final payment.
Withhold final payment
Never pay the final installment until work meets your expectations. This is your leverage. Once you pay, motivation to fix issues disappears.
Escalate if needed
If the provider won't correct work, file a complaint with your local licensing board. Contractors value their license and will often settle rather than face board action. Some areas have small claims court or mediation services for disputes.