Asset Acceptance LLC is suing me...

3 yrs ago I obtained a credit card from Wachovia Bank, with a $5000 limit. I used it to consolidate debt, made regular payments, but on occasion would bump the card up to its limit. Being in the military, I deployed out, and upon my return discovered that the person with whom I'd asked to take care of my bills failed with Wachovia. They'd sent while I was away notices (of which I was not informed), and Wachovia was later acquired by Chase Bank. When I returned home, I wrote to Wachovia for new statements and gave them my new address. I heard nothing until yesterday, when I received a summons that I was being sued for the $4800, plus $890 in legal fees and 10% per annum. Any suggestions?