Need help on garnishment and arranged plan payment

I had a student loan which I was not able to pay on since I was unemployed...I recived a garnishment letter and agreed to a payment plan since I knew I would return to work as a substitute teacher when school began. I was told they would send a stop garnishment letter to my employer with my first payment. Well they received their first payment in aug and I received my first check yesterday sept and found I was garnished. Another payment for them is due today so I contacted them in regards to this. I was spoken to rudely that it was my fault to have let this go on as long as it did, and that they would not consider that garnished amount for this months payment. That they would send a release for garnishment but they were not sure how long that would take. I told them the person I spoke to never informed me of this and shouldn't that be on the recorded call and the gentleman stated sometimes calls are recorded sometimes they aren't. and this was the supervisor! He was being extremely rude and then hung up on me...is there anything that I can do?