trying to settle debt with law firm working for CA

Bear with me, this is a long post.:)

I received a letter from a lawyer for a CA about a credit card debt that is still within the SOL. The letter threatened law suit if I didn't make payment arrangements with them. I called the CA to see about settling this and was told to call the legal dept. of CA. Fine. So I call legal dept. number and they said they can't do anything about the debt(that they own) and I need to call law office. I called the original credit card company instead to see if I could pay through them, and they said no, that they sold account to this CA and any payments would have to be through them. So this is what I want to do: Write the lawyer a settlement offer and send certified mail. I want to mention in the letter about my financial hardship and that under the law they can't garnish my wages because I don't make enough for them to take any of my pay (I would site the law in my state). After a week if I get no response, I would call law office and try to talk out a settlement for a lump sum. Any thoughts on this? Anyone else gone through this or knows more about this, I would like to hear your advice/knowledge.