Product: Credit card or prepaid card

On XX/XX/XXXX I was notified that my credit card was placed on a restricted basis, by the fraud department and that the company Capital One,  was wanting to verify my social security # and would only reactivate my card once the investigation was completed. At that time, I contacted the office telephone # on the form letter and spoke with each individual listed was advised of the following :XX/XX/XXXX XXXX -- a form letter was mailed by US mail in the next 5 to 10 days. 
XX/XX/XXXX XXXX -- notes show letter mailed, but not received by myself.

XX/XX/XXXX XXXX -- - yes, she reviewed my notes but couldn't help, would have to speak with Case Worker -- ID XXXX. 
XX/XX/XXXX XXXX -- he advised me that he couldn't help resolve the issue, couldn't answer my questions as to the relevance of needing my social security # -- indicated that I would need to speak to case worker -- that he would email the individual case worker handling my situation and leave a message requesting that the case worker return my call. Turns out that the case worker 's name is XXXX. Today is XX/XX/XXXXand I have not received a call from XXXX. 
XX/XX/XXXXXXXX, spoke with XXXX, she indicated that she couldn't answer my questions -- made contact with XXXX who refused to take my call. I spoke with XXXX 's immediate supervisor -- Case Worker XXXX ( I wrote down XXXX as name, may be different ) who indicated that she was getting from push back from XXXX. Was advised by XXXX ( sp ) that a social security release form was being mailed. ( Did receive on XX/XX/XXXX. 
XX/XX/ XXXX -- Spoke with XXXX, wasn't sure why they needed social security information -- as they had this information in my application -- would forward an email request to XXXX requesting that he contact me. 
XX/XX/XXXX XXXX -- spoke with XXXX, who forwarded me to XXXX in Fraud Department, who couldn't answer my questions ( XXXX XXXX Department Case Worker # XXXX ), again indicated that he wuls email XXXX, requesting that he contact me. 
XX/XX/XXXX XXXX -- spoke with XXXX can explain, as this is policy. Attempted to contact XXXX -- no response, will forward an email requesting that he contact me. 

My question is rather simple : Why does Capital One need my social security # at this time, as they have all of my pertinent information at the time which I submitted my original application, which was approved over the phone without speaking to a live human and second -- when I requested an increase in my line of credit, it was granted within minutes of being submitted. 

After all of this run-around, I advised the office, that I wanted to close the account and requested that someone of authority, apply my earned rewards points to my account and submit an updated monthly billing, which I would pay immediately. Current balance is {$40.00}, with a rewards balance of {$7.00}. Of all the individuals I have spoken with, no-one has the authority to comply with my request, nor have I been able to speak with a decision maker who can complete this transaction. 

Lacking effective communication -- two way communication, hearing & responding to my request in a reasonable manner, just allows this issue to linger in limbo, without being resolved. 

My goal is simple -- please have a responsible, decision maker within Capital One contact me, who can explain why after the original application was approved, a request to raise my credit limit was granted and all monthly payments have been completed on time, why they need my social security # verified. Utilizing today " secure '' internet -- what is the real issue here? 

My goal is to resolve this issue and move on.