Paying debt on time but judgement shows on my credit report

I was contacted in Jan 2010 by a collection/law office Pressler& Pressler regarding a debt I owed. I made an arrangement to pay a specific amount monthly until the debt was resolved. I was told that if I defaulted on the payments my wages would be garnished which I understood. The law office/collection agency sent me paperwork to sign stating that I agreed to the terms, I signed the paperwork and it was sent to the civil court to be filed. I made my first payment in Feb 2010 and have made payments every month since on time. On 7/13/2010 I pulled my credit report and found that a Judgement had been entered against me and now shows on my Credit Report even though I did not default on the payments. The Judgement was entered and placed on my report in March 2010 even though I had made our agreed upon payment starting in Feb and every month since. Although I signed the paperwork I was led to believe that this wouldn't effect me as long as a paid the debt which I am doing and intend to do until it is paid off. I understand that this information will remain on my report for 7 years. This is not fair and it hinders me if I apply for anything, even a job. Is this legal? Of course the Adam @ Pressler& Pressler told me there is nothing I could do because I signed the judgement. I find that hard to believe since I did not default on payments but the public record indicates I did. This law office has a reputation for of strong arming and not doing this that are ethical or always legal. Unfortunately, I found this out after all the arrangements were made. How can I fight this and get this removed since the information was prematurely entered on my credit report and public record? Can I appeal to the Judge even though I signed the paperwork which I didn't fully understand or should I say was mislead to do by the collection/law office. I really need help any advice or instruction on how to proceed this matter. I want the negative information removed. Any assistance would be appreciated.