My husband consolidated his student loans about 2yrs ago but missed one, or could not consolidate it or something. Basically, he got a couple of quite nasty letters about a debt he owed for an out of state school he attended.
At that time, we wrote a letter stating that we could not manage to pay off debt in full but wanted to make monthly payments. We also asked for the debt to be reduced to the original amount (my husband is not sure what this amout was).
We got a letter back saying they would not accept anything but the full amount of the debt, so at that point, we ignored it.