legal rights to tax garnishment paperwork?

[GuyBen]

I owed taxes and I got garnished through my employer for the money I owed. My check stubs show the info on the garnishment and how much was taken out. I was let go from my employer about 2 months after I finished paying off my taxes (was told business was slow). About a month after I was let go I received a letter from the IRS saying I still owed the back taxes. I was confused by the letter so I called my work and asked them for copies of the IRS paperwork they had received regarding my back taxes. I had copies of the paperwork in my work email, witch I forgot to forward to me for saving (big mistake). My boss said no problem he would print out the documents and mail them to me. I never received them. I forgot about the issue until I did my taxes for 2010. The IRS kept my return for 2010 and when I called them they reminded me that I still owed the back taxes. I contacted my former employer again asking for the paperwork so I could prove to the IRS I did pay. They said they would email it to me. I never got it. The next day I emailed them again and asked them again that I needed the paperwork and that it was very important and that I also needed to know where they mailed the money to. My ex boss said he would pull a report this weekend. The weekend passed and he never sent anything. I'm not sure whats going on but it seems that they are not being very helpful about my situation when all I want is the copies of the paperwork that the IRS sent them, witch I know they have because I did have copies of them on my old work computer. Is it weird that they keep saying they will send me the information and then just forget about me. The business is just a small mom and pop run buisness, only about 10 employees. Do I have a legal right to sue them for the information I need??