Conspicuous attaorneys

I received a letter of demand from this company in July 2019, requesting that I pay or make arrangements to pay off the debt owing. I explained that I had paid up this account in 2018;in fact the bank reissued me a credit card for being a good client but I refused it. They now request me to please furnish them with the letter showing my account is paid up....which was issued ONE YEAR AGO! Don't trust this company.....if they even are an attorneys company because they use ********** infomation regarding accounts which you had 4 years ago. Dont pay to them at all! I have no option but to refer them to the hawks if they continue to harass me.