katie_meehan, this is my experience with a debt management plan via CCCS in Richmond - I started the four-year plan (they said 4 years, but the creditors' agreement letters stated 5 years?!?!) in Feb 2009. They were able to lower my interest rates from upper 20s on all cards to 18.9%, 9.9%, and I think 7.9% was the lowest.
I was pretty shocked that they couldn't get them down to below 5%, and maybe 0% temporarily while I got my finances in order.
I paid for four months, until last month (May). I was fed up. My counselor wasn't returning my calls or emails. My accounts were still being listed as 'past due' and the banks were still calling me!
When I missed that May 6th payment to the creditors, the banks called me even more. Well, it's late June and guess what I did yesterday? I called all of them back. I'm a putz and easily intimidated and shy so I was very nervous about calling them myself. I'm not good at negotiating.
I called Citi first. Have an 18k balance and they had lowered it to 9.9%, which meant I was paying $150 / month in interest and it wouldn't be paid off for almost five years! Ugh. The lady said, We can get you back into a self-administered DMP program and continue the 9.9% interest. I said, Look, I want to get rid of this - I'm broke (told her my lost job / new job at less salary true story) - can't you give me a better rate and let me pay this off more quickly? Well, she wasn't happy about it, but she put me on hold and came back with this offer - 0% interest for 40 months. I took it.
Next call was to Bank of America. 2 cards, the first card had 18.9% and the second had 7.9%. The counselor couldn't negotiate the rates. She said that 'due to regulations', they can't lower the rates anymore. I said, Well, I don't know what I'm going to do - I guess it's time to go back to the bankruptcy attorney.
She put me on hold and came back with this offer - a settlement for both cards at 20% of the total, payable in four installments. The catch is that the settlement must be completed within 90 days.
It will kick my you-know-what, but if I eat ramen and sit in the dark, I should be able to make those payments. And that debt (which is half of my total) will be gone in late September.
I'm going to skip payments to my other creditors to pay the B of A settlement. I know, I know - not good - but it's what I have to do to get half of my massive debt settled. And my credit is already trashed. Once B of A is gone, then I can call the other creditors and start negotiating with them. I can deal with collection calls for three months.
I had talked with a bankruptcy attorney (you can get free consultations with most) about filing for Chapter 13. He thought I should do it. But I don't want to, for a variety of reasons. People will tell you that you must pay taxes on debt settlement. Well, yes and no - it's a complex thing, and depends upon your assets and liabilities. If your liabilities are more than your assets, then no, you don't pay tax on settled debt.
And I suspect that - for most of us on this forum - our liabilities outnumber our assets.
Chapter 13 is very invasive and - surprisingly - more traumatic than Chapter 7. I've accompanied friends to both types of hearings and I was surprised at the differences. I guess because 13 is essentially creating a court-ordered DMP, you're in the courthouse a LOT more, dealing with the trustee all the time, and so on.
I'm just mentioning the bankruptcy stuff because you might be headed there (if you can't make minimum payments), or thinking about it.
After settling with B of A and Citi, I feel like such a weight has been lifted off of me. It's amazing. I don't mind struggling to make those payments if I know there is light at the end of my very long debt tunnel.
What you need to do is what I did - stop paying and let them call you for a while and then call them. If you can't pay, then you can't pay. If they were willing to negotiate with me (the worst negotiator in the world), then trust me - you shouldn't have any trouble.
DMPs are a waste of time and money. They do absolutely nothing. In fact, I am proof that you can do a better job yourself in a mere five minutes.
With the economy in shambles, banks are only getting 5 cents on the dollar for discharged debt. So any settlement will be better than charging off your account into collections, or watching you go into bankruptcy and they get nothing.
That's my long reply.

Good luck!
Oh, and yes, not paying will trash your credit. That's the price we pay for getting the lower rates and settlements.