Product: Credit card or prepaid card

I had been a Chase cardholder for over a decade. I have never missed a payment and my account has always been in excellent standing ( as reflected on my credit report ). I tried to purchase some meds that I get by mail order and my payment would not go through. On XX/XX/XXXX I called the customer service line and was informed that my account was closed on XX/XX/XXXX and a letter mailed to me ( which I have still not received to date ). On XXXX and XXXX I made three extra payments, with nothing due at that time. This year I was able to pay off all credit card debt and now pay purchases as they post or at least pay off the card in full every cycle. I did not realize that Chases online system auto-populates the payment funding account to the last account you used so the payments tried to pull from savings that I dont often use. As soon as I realized what happened ( before even receiving notices ) I paid the card from my checking account with I had originally intended. 
Chase has used the returned payments as a reason to close my credit card. There was no warning or communication that these returns could cause negative account consequences. The returned item notices gave no indication of closure and even thanked me for my business. They also did not charge me any, so it seems that it was not even serious enough to warrant a fee. Clearly, the decision to close my account was not made at the time of the returns but almost two months later. The timing is suspicious. I had an {$18000.00} credit line which closing could affect my credit score. The only reason I can see that they would review my account and close it almost two months later is that they are using it as an  excuse to close my account because I dont carry a balance ( they dont make interest off of me ) and I redeem about $ XXXX {$60.00} of points in statement credits per month ( which there is nothing against in the account agreement and the whole reason I opened this card ). The reason provided to me over the phone on XX/XX/XXXX by XXXX a supervisor ( who refused to let me speak with anyone higher ) was that my account was closed because of the returned payments. However, according to my account agreement, there is no clause that states returned payments could result in account closure. The only clause that deals with returns state We may charge this fee if the payment you offer to us is not honored, is returned unpaid, or can not be processed which has nothing about closing an account ( and was not charged ). The only other clause  that allows them to close an account is We are not obligated to honor every transaction, and we may close or suspend your account. Sometimes we close accounts based not on your actions or inactions, but on our business needs. however the reason given to me was based on my action and not a business need. It is clear in their agreement that my contract/account was not terminated in a legally allowable manner ( see attached account agreement ). 
I called on XX/XX/XXXX and requested to speak with a manager. I was  transferred to XXXX a supervisor who kept telling me what dont you understand, you had a returned payment. XXXX stated they dont have an external email so could not send me my account agreement, he told me it is not available online, and they could also not send me it via the online messaging system. He also would not cite to me the clause that gives them the right to close it. Seemingly he did not want me to look at it. Also, he stated that a loan is not a contract, which is grossly incorrect. On XXXX I messaged chase that I had a right to obtain my account agreement to which they sent me a direct online link. Why was this not supplied immediately the first time I called on XX/XX/XXXX. 
This closure appears to be a deceptive way to get out of their relationship with me since they dont see my account as profitable, with complete disregard for their effect on my credit and overall financial health. I also have all my automatic I have to switch, not to mention the fees I would have incurred from other companies if those payments bounce since I did not receive any notice it was closed. They say they sent me a closure letter the same day the account was closed XX/XX/XXXX, but then why does it not show up in the Notice and Letters section of online banking ( See screenshots attached ) like the returned payments notices do, which suggests a closure notice was not actually sent. To date, I have not received any closure notice. This to me appears to be a violation of Reg Z closure notice requirements, a breach of contract/account agreement, and the whole issue is a possible UDAAP violation. 

I have worked in the financial sector for over a decade and we would not dream of closing someones account who 1 ) for a reason not legally supported by the account agreement, 2 ) when the client had over a decade of excellent account history, and posed no threat to the financial institution, 3 ) for one mistake, that was an extra payment, 4 ) that did not negatively impact our financial institution, and 5 ) that was the fault of the online system auto-populating the  wrong payment account. Their actions are unconscionable and I am being retaliated against for not being a profitable client who is financial responsibility and does not regularly pay interest anymore.