Citibank Credit Card Complaint

Citibank Credit card department,

Unsolicited issuance of credit card Arizona

A few weeks ago I received phone call from Citi Bank. Since I was working at the time they left a message stating to call them back about my - Card. I did not return the call as I have not applied for a card with them nor do I have any relationship with them what so ever. Last week I checked my credit report and low an behold they had made a credit inquiry and a new account was showing opened under my social security number. I have tried to call them repeatedly but all that happens is that I am left on hold. I have even tried to call during non peak times. I have not received any card in the mail and I do not want one. Like I said I rarely apply for credit and I have n't applied for any credit since I bought my car two years ago. I would like to get this removed from my credit report and most of all I want to know how they got my social security number.