Citibank Debt Collection Complaint

Citibank Debt collection department,

Credit card Improper contact or sharing of info Contacted employer after asked not to Massachusetts

These people call from different numbers and when I call them they never address themselves. I do owe a credit card debt but I can not make any payments right now since i only work part time and I am in school. They keep calling my place of employment which is illegal and asking my co-workers personal questions about me. I need this too stop.