I elected my arbitration rights and they sued me anyway

I have credit card debt I defaulted on that was sold to a collector.I dv'd them and they sent a few statements in return.Several months later I recieved a letter from an attorney saying the collector had retained them to collect the debt.The original account number was not listed anywhere in their letter. It also said I had 30 days to dispute the debt. I responded just 2 days later with a dv letter sent with delivery confirmation and both disputed the debt and elected arbitration which waives them of their right to litigate the matter in court.
They responded by filing suit against me in court.I have not recieved a summons but called the court house and there is one there so i am going to pick it up myself.The court office told me the court date is scheduled for the 27th and was filed on the 23rd of Dec.

I recieved a solicitation letter from a local attorney telling me there was public notice of me being sued and they could help me.Thats how I found out I was being sued in the first place or i'd never have known i was being sued. From what i have read I feel im ok because they clearly recieved my election of arb before they filed suit and I can prove it.
I need to file an answer and know nothing about how to do that and can n ot afford an attorney. What is best for me to do, an mtd or mtc or what? I have many questions.Does a lawfirm retained by a collection agency have to validate debt? I never got any validation from the attorney. Will I have to tell the judge what part of my fdcpa right were violated? I am in TN and don't know how to defend myself in court at all.
Do i need to contact the lawfirm and let them know they can't sue me because I electred arb or just file an answer and see what happens? PLESAE HELP!