Nationstar Mortgage Debt Collection Complaint

Nationstar Mortgage Debt collection department,

Other (i.e. phone, health club, etc.) Disclosure verification of debt Not given enough info to verify debt California

I send Nationstar a debt validation letter on - and i did not get any response, i send them a reminder on - and still no response even though under law they have to respond. I called them on - and they would not give me any information. Please help, i need this information for my litigation