Product: Credit card

Hi, My citibank " Thank you preferred credit card '' has been closed since XXXX 2016. 
I do not know the reason ; therefore, I called the customer service and want to reopen my credit card and give me the reason why my credit card has been closed. The staff in customer service just keep saying we do not have enough information ; we can transfer to other department to help you. However, the other department said same thing " we do not have enough information " we will transfer to others department. One agent wants me to write a letter to XXXX XXXX XXXX XXXX, SD XXXX or XXXX XXXX XXXX XXXX XXXX, SD XXXX to explain the situation. I did write the letter and went to the post office to send this letter to this department. Nevertheless, the department response to me " we are unable to process your request for us to reopen account without speaking with you '' ( letter uploaded_1 ). I called customer service again, the agent told me you have to write the letter to same address shows above. I was so angry and said I did and they want me to talk customer service. The agent said : I will help you to reopen the account for you. One week later, I received the letter from Citibank, it says : " Unfortunately, we can not reopen your Citibank thank you preffered card account, because it was permanently closed '' ( Letter uploaded_2 ). I am so angry and call the customer service again. The agent wants to me to go to citibank branch. I went to the citibank branch in XXXX and the agent said, we can not help you, you have to call customer service. I use the agent 's phone to call Citibank customer service again ( I do not remember how many times I call the customer service and each time I need to explain 1 hr ). Same thing happened, I have been transfer at least XXXX~XXXX agents and all the answer is we do not have enough information. The agent in the citibank branch, she can not stand this situation ( because it 's been almost 2 hrs and no one can help me ). She picks up the phone and talk to the customer service and said we need to talk to your supervisor. Customer service just said this time we definitely will transfer to right department. However, that department still can not solve the problem and keep transferring and said our manager will call you tomorrow. I give up and just ask them if my account has been closed, how about my thank you points? They said we need to transfer to another department and they will answer you. The department said since your account has been closed, you can not use the thank you points. I talk to them you can check my payment in past two years, I paid my bill on time every month and Citibank closed my account for no reason and there is about XXXX thank you point in my account. Originally, I am going to change this points to update my flight tickets to XXXX business class from U.S to XXXX. The Citibank just say we can not help you. Your account has been closed. That is unacceptable, ridiculous and not making any sense. XXXX Day after, I still not received any call from Citibank and I call the customer service again and want to speak with their supervisor. The agent told me we do not have any record and you have to wait XXXX hrs and the XXXX will call you. I said, the agent told me the supervisor will call me today. He said : sorry, you have to Waite 24~48 hrs. I am going to crazy and he said you have to write the letter to same address above, and I told to agent, they already response to me and want me to speak with customer service. He said that is impossible. This time I write down his employee ID is XXXX and ask him again your supervisor will call me tomorrow right? He said yes He or She will call you because tomorrow is 48 hrs. Guess what? I still not received the call from Citibank. I already spent too many times in these, its waste my time, energy. Please help me to justify Citibank. Citibank is extremely hateful.