Complaint sub-issue: Can't use card to make purchases

In XX/XX/XXXX, My Citi Advantage card was locked simply because my son who is a authorized user tried to connect the card to his XXXX XXXX to have XXXX XXXX. I called 6 times and no one would help me. They asked me, the account holder, questions and I answered them all, but the only questions they asked were " do you have another acct with citibank and do you have a land line number. My answers were no because I don't. 
I gave them my phone no but they said they could not verify my acct by my no, so I told them to ask me any other security question and they said they could not ask me anything else. I spoke with another supervisor and he asked me some different questions and he was able to get my card unlocked so I could use it again. { keep in mind that i spend thousands of dollars on this card monthly and make thousands of dollars in payment }. 
In late XX/XX/XXXX, they flagged my card again and all my son did was go into a store and attempt to get a pair of shoes. I changed phones from a XXXX to an XXXX and it required a card to be registered on it, as all XXXX  products do. When I attempted to add this card to my phone, it locked my card account again. I spent over 3 hrs working on this and talking to multiple representatives, and no one would help me. I kept asking if you can not verify my account by me, how do you do it. They could not tell me and did not care or want to hear anything I had to say. I finally spoke to another supervisor and he asked me if there were anyone in the household that he could send a code to so I gave him my wife 's no. He sent her a code, she read it to him and he unlocked my account. Never seen anything like it before. That could have been anyones number, and they used that to verify my account and she isn't even on the account of have nothing to do with it, yet they can not verify my account using MY own number or my childrens ' no. who are authorized users on the account.. 

Now today, XX/XX/XXXX I received a letter from Citi Advantage telling me to complete my XXXX XXXX activation. Gave me a number, and after calling it, they again locked my acct, and would not verify my account with any info I gave them. I informed them to please unlock the account as my XXXX  children who are in college have no money without my credit card, and they stated they did not care, they were not doing anything until I got a letter they were sending out to me, yet again. The representative I spoke to was XXXX, and there were 2 supervisors, named XXXX and XXXX. They never tried to help and just told me they were not gon na do anything until I got the letter, then I needed to call them like I did today after I got this letter. I have never seen anything like this, I am disgusted, very disappointed and feel for some reason I am being discriminated against. I really dont know what to say about all this. My kids are in school not without money since Citi card did this for the third time but this time is the last straw. 
The last supervisor I spoke to ( XXXX ) lied to me or was reading incorrect info in my account, he stated that I was asked several questions and I did not get any of them right. I informed him that I was one asked if I have another acct with citi card and If I have a land line no. and I answered no to them both, he then stated that is not what is noted here in your account, but he refused to tell me what was in there. 

I want something done about this, I am a retired XXXX XXXX XXXX XXXXXXXX XXXX XXXX XXXXXXXX, and this is the treatment I am getting from a card that I use and spend thousands of dollars on monthly. I want something done to these reps, supervisors and Citi card.