Validation: make sure you know the debt is yours and legitimately owed.
Don't avoid or ignore calls or letters.
If owed, avoiding will only continue collection activity.
If not owed, inform them, so the collection activity stops.
Work out a payment plan: be honest, work out an arrangement and stick it or communicate. Pay what you can afford.
Get Help: If you need help get it. If you cannot pay your bills or are in debt, a consumer needs help to get out of that situation. One resource askdoctorbebt.com.
The website Ask Doctor Debt www.askdoctordebt.com is a great resource for folks that are having trouble with their finances. There are a ton of questions and answers and even advice on dealing with collection agencies.