No, they are just planning on suing you for what you owe, but they are trying to give you an opportunity to stop that by paying.. That is handled through civil court, not criminal. You'll be on the hook for what you owe and likely court costs and their attorney fees. So you're really looked at more than the balance you'd owe them.
If they receive a judgment, they will garnish your wages they'll take out 25% of your paycheck, each time you get paid. A garnishment is good for 91 days but if the balance isn't paid, they will get another one and keep doing that until it's paid.
If they receive a judgment, a judgment remains on your credit for 10 years.
It's really in your best interest to pay the balance or work with them for a payment plan. Since it's in collections, you can likely negotiate for less than you actually owe.