Wages STILL being garnished after agreement was met.?

My student loans defaulted , so to get them out of default Icalled my loan servicer . They set up an agreement that I would pay an amount in addition to the garnishments for 5 consecutive months and then the garnishment would be removed. I did NOT miss a payment , signed all of the required forms and made all of the payments on time. The garnishment was supposed to stop on July 10th but still hasn't. I called my servicer about this and they said there had been a mistake and that they would clear it immediately. I received my pay stub today for this weeks paycheck and they are still garnishing. My question is...Is there something I can do about this? Who would you file a complaint with?