Student Loan company harrment?

I've got several student loan bills that are in default or overdue because of a lack of steady income. (my job gives me 10 hours a week now at $8 an hour, obviously not enough to cover $700 a month in bills.) I am in the process of applying for a financial hardship forbearance. My question is, they called my grandfather this morning looking for me. Are they legally able to do that? He was not a co-signer and has nothing to do with my outstanding debts. I am livid. He's 81 years old, and there's no reason i can see, why they should be calling relatives of mine that are not tied in directly with this matter.