How long can a credit card company go after you for a debt?

I just recieved notice in the mail about a credit card I had canceled over 10 years ago. It was a $500 credit card but they claim I now owe almost $4000. I looked on my credit report last month and that debt wasn't there. About a year ago it was on my credit report but when I refinanced my debt loan they said it had been taken off. When I checked my credit report last month it was still off. Now today I get a letter in the mail claiming I owe them money still. Can they put it back on my credit report after the statue of limitations has run out? In Missouri its 10 years for a credit card. I'm willing to pay them $500 for the origional credit card but I don't know where they have come up with this $4000. I'm slowly rebuilding my credit but if this goes on it I'm going to have to just give up and declare bankruptcy. I'm 29 so I'm still young enough to recover from it but don't want to file even though with this it puts my debt way over $10,000. (Capitol One was CC Company)