How to complain smartly

In the US, there is a strong framework of both federal and state law for consumer protection. Should you be affected by issues concerned with defective products or services, you need to be aware of the laws and regulations which exist to alleviate and resolve your problems.

How to Complain and Get Results

Be Prepared.
Face the Issue.
Stay Cool.
Work Your Way Up.
Pick Worthwhile Fights.

via 59edu

How to Complain and Get Results

Find someone who can help, preferably someone who doesn't look completely distracted and stressed out.
Smile, lean in and speak to them as if they were a confidant and you are revealing a secret.
Explain your situation calmly and quietly.
Have a specific result in mind, and request it. Do you want a refund or a replacement? Do you want an apology? Do you want a problem corrected? Be firm, but reasonable.
Remove emotion and look at the situation objectively.
Smile
Once you've found someone to listen to your story, be sure to thank them for their time.
Finish with something like "You can understand why I'd ask this, right?" or "Why I'm a little upset, right?"
At this point, the employee will probably say he/she needs to speak with a manager.
Finally, whatever the result, thank the individual for his/her time and attention.

via wikihow