Illegal actions do I have any?

I had a credit card through Target and one day received a letter stating that I owed RJM Acquisitions LLC for this account. I was giving 3 options to pay off. Target was still listed on my credit report. So not knowing what I know now I entered into an agreement to pay them for this debt. During payment the Target debt was removed from all of my credit reports, but I am still making payments to them. Also my last statement they have added my maiden name to the center of my address label. how did they get this, was it obtained illegaly. I did not provide with this nor authorize for them to find this. Is there anything that can be done