Product: Checking or savings account

Navy Federal keeps taking money out of my personal Navy Federal account and applying it to their Navy Federal Credit Card without my authorization because my credit card was around 30 days past due. Apparently, their disclosures allow them to take money out of one 's personal Navy Federal checking account without your authorization if you are past due on their credit card. 
I have a personal checking account with Navy Federal and also have a credit card under Navy Federal. I have hit financial hardship unfortunately so fell past due on my credit card behind one month. Navy Federal started taking all the funds I had in my personal checking and applying them to the past due amount of my credit card without notification or authorization and leaving me literally with a {$0.00} balance. What is really messed up is this is money I really needed to buy basic necessities - groceries and gas, particularly for my little one. 

On XX/XX/XXXX, they transferred {$9.00} ( all that I had at the time ) from my checking to my credit card, on XX/XX/XXXX transferred {$200.00} to my credit card, and then again on XX/XX/XXXX transferred all {$110.00} I had in my account to my credit card. All three times they took all the money I had in my checking account resulting in my account having a {$0.00} balance. They didn't even leave me a single {$1.00}. 

I called Navy Federal on XX/XX/XXXX explaining the situation and stated that I am not trying to get out of paying my credit card, but that I am in a financial bind but have every intention of paying and need a little time. The representative agreed to reverse the {$110.00} if I would agree to start making payments beginning in XXXX so I agreed. I literally just started working with a XXXX XXXX XXXX during this time, but because I was in need of the funds they took, I went ahead and agreed. 

Over the weekend I saw that a {$9.00} charge was denied, and I was charged a {$29.00} " returned check fee. '' Again the funds were there until they zeroed out my account days before and again gave me no warning. So I called Navy Federal again on XX/XX/XXXX, explaining that I am having a financial hardship, how they keep taking all of my money out of my account leaving me with nothing which is putting me in an even worse bind, and the fact it was all essentially going to interest. The representative ( I believe it was the credit card department ) looked to see if she could refund me back all of the {$320.00} they took out ( not including the returned check fee ) and it was denied. They denied crediting back the money they took without authorization because " I was working with a third party debt agency '' and therefore also would not honor the {$110.00} that they said would be refunded back to me just days before. Separately, the first customer service agent did credit me back the {$29.00} returned check fee before I was transferred to the credit card department. So I guess that's something. 

I'm not perfect but try to be a financially responsible person and do not try to live above my means for myself or my family including managing my credit cards. My situation is unfortunate and I am trying my absolute best to stay afloat. I just can't wrap my mind around how a bank can legally take funds out of your account, and multiple times at that, without your authorization ( excluding court orders, IRS ) to pay on a credit card.