can a collection agency legally collect a charged off debt t

Unfortunately, there is nothing you can do with the original creditor because they sold the debt to an outside CA.

You have to confirm that you are contacted by the right company that has your info. You are supposed to get the debt details in your mail within five days after the first call. If you hear nothing, send a DV letter to the company that called you. Your documentation should prove that you are taking care of the matter and want to pay to that company your file is with. This will help you in case you get a court hearing and the problem is not resolved.

I think it depends on the terms that the debt was charged off. If the credit card company charged it off themselves after exhausting all their own internal collection attempts than yes, they can than sell it to a 3rd party collector who will than try to collect again (usually with much more aggresive means). However they are still required to validate the debt if you request it. But if the balance was legally settled for less than the full amount which an agreement between you and the credit card company, than no, they can not turn around and sell the balance to a 3rd party collector. If that is the case than you definitly need to dispute it. Hopefully you held on to your settlement letter. You can always try to get the collector to settle for less than the total due. The longer the account ages than the better the settlement offer you are liable to get. However keep in mind that any abount over 600.00 that they write off you will have to declare as income at tax time.

I have a scheduled hearing from a collection agency for 10000usd the debt had been charged off in 2004 by the original company what should I do they would not even settle for any less from that amount

What type of debt and what state are you in??