I just received a letter from a law firm soliciting their services for a apparent lawsuit filed against me by American Express. I looked up the case number and found it was filed on September 23rd, 2013. Acccording to the letter I must respond in 30 days of the filing but I still not received a summons. There is only seven days left to answer and I have been completely caught upwith payments since August and continuing making payments on time. How do I answer this lawsuit without a summons?