Complaint sub-issue: Credit card company isn't resolving a dispute about a purchase on your statement

I bought a set of headphones on XXXX on XX/XX/2017 from XXXX seller XXXX for {$XXXX} for a product called XXXX XXXX  XXXX XXXX they were high fidelity quality. I won the auction on XXXX and paid through XXXX using my Discover card. When they arrived they appeared to be in good condition except for sound quality. I tried them and they didn't appear to sound as they should have, I tried to reach the seller by XXXX but XXXX shortly after suspended the sellers account and I couldn't get an answer back. I sent a several emails to the seller and I never got an answer and because I didn't use XXXX for credit, XXXX wasn't able to help me because I used Discover Card instead. I contacted Discover Card, made a dispute on the item. Discover Card applied credit back to me based on investigation but about a month later,  Discover didn't contact me at all and they took my money back as they claimed when I had to search on their site to find the answer that I didn't return the item. I explained to Discover, the sellers account was suspended and I had no way of reaching the seller, I didn't get any replies back and second, I didn't have a return address on the item either, so how could I send them back anyway besides no way to reach the seller. Third because the item was supposed to work, the seller didn't reply back on sending back either or a shipping label or anything. I told this to Discover   disputes department and two I provided snapshots of the sellers account on XXXX was suspended for verification and I had no communication back. Discover didn't provide any decent answer to me, they make it a mystery how they communicate as well. They provide no text or email on the disputes but only file attachments only, no way to tell them but to make a snapshot on a XXXX   page on content, make a snapshot of that communication what I want to say to them and send as a jpg file it is a bogus communication effort on their part. For example when I normally use XXXX I use XXXX credit and their department provides all the necessary tools so sellers and buyers can communicate but with Discover card, it is by far the worse way to communicate using only file attachments and three their customer service is really bad to talk to they tell you to use the disputes file to send information but it is so so limited. You dont get a representative or a file number or a department to call or them to call you and etc. For example, you have to go looking on their site to locate the disputes and it isnt easy to use but when you find the information, you find they rejected your claim and no answer either. They tell you will get an answer in the mail, well to get an answer, I got answer with no provided information on their reasons or even the communication of how I can review and also, their letter took 5 weeks to get in the mail. They tell you if you want to continue, you need to file more information, it doesnt make sense and lastly they tell you as a type of threat they have contacted the credit bureaus on your dispute also. I never had a credit card that will treat me like subhuman and make no information available but a mystery investigation like Discover has done to me. Anyway, Discover Card rejected my complaint and they awarded the seller the money on headphones I have that are defective and Discover Card says I need to show information I sent them back, which I explained over and over that the sellers account is suspended and there is no address and way to communicate with the XXXX seller. Also the XXXX sellers account has still not been restored either, it is still suspended. Personally the system that Discover Card uses for disputes is plain awful compared to other credit card institutions, the way Discover responds and handles their disputes with their customers is not only bad but they have hundreds of negative online reviews about them from prior customers claiming the same thing. Seriously, how can Discover accept me to send an item back without a return address, no communication from the sellers from emails and their XXXX account suspended? And Discover rejects my claim? The communication at Discover is more than a problem I have witnessed but also something that needs to be addressed how they handle their disputes with all their customers. If this is how they treat me and this is their system of communication, then I am filing a complaint not only on them being unfair to me but also they have corrupt disputes department because this is not just awful but is it a system of denial without merit on their part. It is credit card corruption as I don't trust Discover Card, I think they misled people and they take advantage of their customers as I witnessed.