Tax Return garnished for Federal Student loans

I filed on April 3rd and called the number given to me to figure out if I had an offset. I learned I had one and was gonna have my return taken and to contact Us Dept of ED. I though they could not collect between March 13th and September 30th? I would not bother posting this question but I cannot contact them now until Monday and was wondering if anyone had answer or is dealing with this themselves?