Product: Credit card or prepaid card

I have been a long-time customer with Capital One, holding a Venture credit card, a XXXX credit card, and an auto loan. On XX/XX/XXXX, both of my credit card accounts were, without warning, spontaneously closed. Upon reaching out to Capital One, they claimed this was due to numerous reversed payments. However, I was unaware that the payments had even been reversed in the first place ; upon submitting payments through the mobile app, I always verified that sufficient funds were in my account at the time of payment. However, payments would either take unreasonably long to pull from my checking account, or wouldn't pull at all despite sufficient funds in my account. For example, for my payment made on XX/XX/XXXX of {$1500.00}, I had {$1500.00} ( roughly ) in my XXXX XXXX  checking account at the time. Then, the payment was reversed on XX/XX/XXXX under the transaction name " XXXX XXXX XXXX XXXX - XXXX ''. I logged into my mobile app on XX/XX/XXXX and noticed this at that time. However, upon reviewing my XXXX XXXX  checking account, I still had the {$1500.00}, sufficient to complete the requested payment. Thus, I decided to begin making smaller payments ; I made a {$500.00} payment on XX/XX/XXXX that has STILL not been withdrawn from my checking account at time of writing. A further example : on XX/XX/XXXX, I made a payment of {$1300.00}. This did not appear on my account until the posted date of XX/XX/XXXX. Then, it wasn't until XX/XX/XXXX that Capital One attempted to withdraw the funds from my checking account. As a result, automatic transactions that otherwise would not have had an impact reduced my checking account balance just slightly below the {$1300.00} payment made. As a result, I received another " XXXX XXXX XXXX XXXX XXXX XXXX XXXX'. I immediately rectified this by paying a much lower amount of {$1100.00}, which evidently processed just fine. 

Upon discussing this matter with Capital One directly, I was advised that there was no remediation possible. They claimed to be unable to reopen my account unequivocally. They claimed to be unable to open a new account with the credit information they had available ( I had recently applied for a limit increase, so there is no reason they shouldn't have sufficient information on hand ). They claimed to be unable to provide any information on the decision, other than " this was a decision made by capital one due to multiple returned payments ''. Due to Capital One 's refusal to seriously address the matter, I am now forced to file this complaint. Capital One aggressively marketed their mobile application for quick, on-demand payment processing. It seems highly inappropriate and unfair for my usage of said mobile app exclusively for payments onto my accounts, and Capital One 's mishandling of those payments vis a vis delays, to result in punitive measures taken against me. I feel that their mobile app was deceptively advertised, giving a false impression of the speed at which payments made through the app were to be processed. It almost seems as though they wanted to avoid allowing me to utilize the {$400.00} worth of reward points I had accumulated, and to make me reapply for a brand new account with another hard credit inquiry.