Very often if a debt goes unpaid, a creditor may turn the debt over to a collection agency to recover that debt in exchange for commission or percentage of the debt. 

A collection agent has almost the same power as other creditors. They can persuade you to pay or work out a payment plan. If you do not pay, the agent can sue you for the unpaid debt.

A collection agent cannot garnish your wages or seize your property without beginning a court action. The only exception is property given as security for a debt. For example, if you buy a car and use the car as security for a loan, the creditor may seize the car if you default on payment of the loan. The creditor does not have to sue before seizing the car.

If you do not address the collection, you will not be able to obtain other credit such as a mortgage or loan.