HELP OFFSET IS GONNA RUIN ME

I recently moved and forgot to change my address with all the people I get mail from. But I had some DOE direct loans around 5000. I got a call at work saying they would garnish my wages. The lady was really nice and we setup a payment plan and I paid 1200 off in the first two months and then its going to be 85 dollars a month after that. Then two days ago she called me to tell me that my tax return for the year would be offset or if I wanted I could pay 3500 right now and settle. I told her if I had 3500 dollars don't you think I would have paid it all of the first time. The whole point of paying the monthly payments and 1200 was to avoid wage garnishments and tax refund offsets. I am setup for monthly payments that are automatically deducted from my account so its not like I don't want to pay it but she said it doesn't matter they will still offset my refund even though I am paying. She also said that my loan would be out of default by September because I am on the rehab program. So I asked her if i could just pay the monthly amount from now until September won't that bring me out of default and she said no you can't do that. Its either 3500 now or tax offset. Is there anyway to get around this?