Northstar Location Services, LLC Debt Collection Complaint

Northstar Location Services, LLC Debt collection department,

Non-federal student loan Improper contact or sharing of info Contacted employer after asked not to Kentucky

This is the second time that someone from - has contacted my employer at home. I told them the last time that this was my employer 's home number and that it was unacceptable for them to contact him at his home. They assured me they were going to remove the number and it would n't happen again, but it has. How do I fix this?