Asset Acceptance issue

I have a question concerning Asset Acceptance. Apparently the company purchased my account from Dell years ago, they contacted me a few years ago and I set up bank drafts to pay the debt. I got a letter not long ago saying I owed over $2000. I have been paying on this account for several years and the debt seems to be increasing instead of decreasing. I have received no contract from the company and I am not sure where the money is going. The only thing I am sure of is that I am not making any progress. I was under the assumption that the debt was being paid to Dell, but Dell closed my account years ago. Can Asset Acceptance continue to charge interest and can they legally sue me for the money? This is worse that having credit card debt. I live in Louisiana and really don't know what I should do. Any suggestions? Did I screw up by trying to pay the debt? I can't afford to keep paying this money and not see the end in sight.