I am american citizen all I did was change my last name because I got married on my ssn card on July 3rd . I have even a receipt stating that I did so.and I called the office where it gets processed and they say it has been verified and processed and sent. So it is no longer there problem it is the problem of the post office . What do I do now.

If they send you a new SSN card but you didn't receive it, call the Social Security Office again. They should be able to track the letter they sent to you.