I searched for something similar to this before I started rehab and couldn't find it, so I thought I'd post it for anyone else looking for it in the future.
My Story:
Sallie Mae loans, defaulted in 2007. Went through various collections agencies, finally ended up at OSI (a division of NCO) last year. USA Funds was the Guarantor.
Got a letter saying they were going to take my tax refund if I didn't set up payments, so I called.
Called around August 1st of last year. They said if I made a payment then they could credit it to July, thus starting my rehab a month early.
Payed August 1st (credited for July), and then the last day of the month.
When my 9th payment became due, they called me a month early, saying if I paid on the 10th of March they could credit it early and end the rehab.
My loans were picked back up by Sallie Mae on March 28th. So some 8 short months later the rehab was done. Default was removed by EX today. EQ it was already gone for some reason. TU still hasn't updated.