Product: Credit card or prepaid card

I applied for a costco visa anywhere visa card by citi cards at our XXXX California, costco location and it was approved and i got the card in mail. Later on i came to know that there will be a annual fee on this card so i decided not to activate that card and cancel this account as my husband already has this credit card on his own name. we didnt want to pay the double fee for same kind card. I called the customer service to cancel my credit card and the customer service rep told me ; give us the security word first to confirm your identinty. I was kind of surprise which security word you talking about as i just recieved my card and i even didnt activate it or used it. She said we cant do anything unless you give us that security word or password. I simply told her i do n't know which security word or password you talking about as i even didnt activate this card yet ; all i want to cancel the account. But she said we ca n't do nothing unless you give us that security word. I asked for the supervisor and she told me you have to fax copy of you driving license ; social security card and your auto insurance policy showing your name and address ; so we can confirm your identity. I fax the paper the next day and called them back to ask if they recieve my fax ok! but the customer service rep. told me you have to wait 24-48 hours and some one will call you back. Three days passed and no one called me back or nothing, i called them back again and asked for the supervisor ; supervisor told me they didnt got the clear coppy of driving licnese and social security so it need to be refaxed ; which i did the next day and called them back to confirm, if its ok this time ; but both customer service rep and a different supervisor this time told me they ca n't tell me nothing this time and i have to wait 24-48 hours and some one will call you back! Its been already a week and no one called and told me nothing. XXXX XXXX, 2017 i got a letter from citi card saying there is some suspicious activity going on your card and call us back to confirm your identity ; i called back today XXXX XXXX, 2017 @ XXXX XXXX PST ; to tell them i recieved this letter and the customer service rep. Started saying the same thing, they are reviewing your document you have to wait 24-48 hours again. When i tried to tell you its already been two weeks i am going back and forth over the phone but no result. She has the same answer she can not do any thing. Wait 24-48 hours and someone will call you back!
I am so mentally stressed out righn now and regretimg the mistake i made applying for costco citi card. No one ever call back from costco citi card customer service, to tell me what is going on. Please help me they are just harrassimg me and not closong my account. All I want is to close my account. I never made any purchase on that credit card or nothing. On XXXX XXXX ,2017 me and my husband went to return a plant we bought in past from costco on my husband credit card but as i gave them my membership card at return counter and they somehow refund that {$18.00} on my new costco anywhere visa card which i want to close. Thats the only transaction is on this card ; a refund of {$18.00} on XXXX XXXX 2017.
Please help me!
Thank you!!