Should I Consolidate My Credit Cards Debt With A Debt Management Company ?? What Do You Think? ?

I have over $20,000 of credit card debt. I am able to pay them off slowly now, but I am thinking of consolidating everything with a debt management program. This program said they will close all my accounts and all I have to pay is a low monthly payment of $500 a month for all my credit cards. Is this a good deal? I am not sure. Thank you for reading and thank you for your time.