Legal Fees for a Paid Up Account

I have been receiving text messages of a final notice to pay my account from these people, I have never heard of them in my life. I then decided to give the number which they provided on the message a call. I spoke to a gentleman who requested my ID number after which he told me that I have an outstanding amount for a Truworths account. WHAT!!!! I settled Truworths via MBD Attorneys( who by the way are just as horrible) and received a settlement letter which I was emailed to Truworths. I told this guy they must stop sending me these messages and he rudley responded that I have legal fees to pay and that I settled the account but not their legal fees, that I must not get him worked up and that if I paid my accounts I would't be getting these messages from the lawyers. Really? What on earth is happening with this company who can I report this matter to? I am super disgusted.