Hospital Bill

Before I had surgery, I set up a buget payment plan with the Clinic, of $45 a month. This was back in 2004.
I have been making required payments, on time. And even have been able to give them a little extra.
They called me, yesterday, wanting full payment of the bill in the next 12 months. I can't afford it.
They said that the original budget plan that I set up, was intended to be for a 12 month period. They conceded that I may not have been told this when I set up the plan.
On the most current bill, it states that the next budget plan installment is due on ______.

I have heard many times, even most recently, that if I make a minimum payment of $5, they legally cannot do anything to me.

Is this true?

Is there any other course of action I can take, since they have not made their intentions clear from the start?

[judg4]

They can still sue...so it best to try to work out something if possible. But frankly often they will not sue if they feel you have no assets etc. to collect.