Old student loan????

i was 17 years old a minor when this loan was taken out and my grandmother was the primary its been 15 years and know there going after my tax return what should i do i dont even have the orig contract and my grandmother has long since ped the school closed befor i could even finnish and they where supposed to find me job placement but the shut down and folded up there tents this has been hauntingh me for 15 years and could realy use some help what can i do please if u can or refer me to some one who can i feel i should not have to pay this of because i was a minor ??? thank u edmund brunning