Citibank Credit Card Complaint

Citibank Credit card department,

Customer service / Customer relations Wisconsin

I opened a best buy citibank credit card recently and before I received the card, I moved. I called them to change my address and even after giving them my ssn and all the information they asked for, they would n't verify my account. I gave them the same information that I used to open the account. They made me send a code to a number that belongs to my father to access my account. After changing my address they told me they would send out a new card. I received an email from them today about returned mail. I called them to see if it was returned from the old address or the new. They told me my account was being investigated for fraud and they could n't give me any other information, not even if interest and late fees would be accruing during this time or how long this investigation would take. This is unacceptable. This is my account and I have all the information that is legally required to prove my identity. I am worried they will hurt my credit as I can not access my account to make a payment. They would n't allow me to speak to a supervisor, though I asked on - separate calls. Please advise.