Product: Credit card or prepaid card

I am not sure if this warrants a complaint, but I am checking to see if this is something that can be addressed via policy or if a company can be pressed to change a company. I have a series of specific problems. 
I was foolish and accidentally allowed a company I should not have to start billing my credit card regularly. They did not provide what they said they would. I initiated a dispute with them, but I had a good idea it would be hard to stop them from continuing to use my credit card. I tried multiple ways to get the credit card to not allow the amounts to be charged anymore. This wasn't a small fee -- it was {$1000.00} a month. ( It was a service that was supposed to help me grow a business, but it was not doing what they verbally said they would do. ). 

But the Discover customer service agent on Friday XX/XX/XXXX said they had a policy of not disallowing a merchant to go ahead and continue to use my card. I was flabbergasted at this so I called up on XX/XX/XXXX and said that I would simply close my account and pay off my bill rather than have to allow the situation to continue. Then the costumer service agent, XXXX, became very accommodating and said of course they wouldn't allow a purchase that wasn't something I wanted. They said they'd stop the payment but indicated that it would be possible, in a year 's time, that I'd have to renew the ban on this merchant. This took about an hour but eventually I was assured that there was a block on this particular merchant. After that, I went ahead and engaged with the merchant, who said they would not longer charge me. 

But XXXX and behold, the merchant didn't stick with their word, and neither did Discover. I had even frozen the account, just in case, but I went back today XX/XX/XXXX and found that Discover had indeed allowed the payment through. I was shocked. 

I have now completely closed the account. They verbally assure me there will be no future payments accepted because it is actually closed. I suppose I have to believe them, though I can't trust anything the agents say over the phone, it seems. I even have a letter from them saying that they had blocked the merchant, so a written letter is also no guarantee. I spoke with a supervisor, who went by the name of XXXX, and who basically said I could dispute the {$1000.00} but that it was essentially my fault for allowing the merchant access to my card. I did start a dispute on the payment, and actually decided to dispute all the prior payments as well, but I am also angry that Discover made this so difficult for me to do. ( To be clear, not disputing per XXXX but they refused to block the merchant at all. I think that is a terrible policy. ) Is there anything that can be done about this? I do not believe that Discover should have a policy that lends itself so easily to defrauding their own customers, and I said so to every single customer agent I spoke to. 

I was very foolish. My XXXX XXXX XXXX could see the whole thing was a scam, but I didn't want to believe that. But I do not think that Discover should have sided so fully and wholeheartedly with the merchant when this was such a large amount and this could have gone on indefinitely. Please let me know if there is anything that could be done about this in the future or if there is any way to push for a change in how credit cards treat their customers. 

Thank you.