Product: Credit card or prepaid card

I purchased a XXXX XXXX on XXXX on XX/XX/2020, this is an electronic device that processes transactions for cryptocurrency and you are rewarded for your participation with cryptocurrency in your account. The day after the sale I messaged the seller because the XXXX ad said free shipping, but I was being charged shipping. The seller said he will cancel the transaction because the shipping charges were substantial, I agreed with this. I got a message from XXXX saying the seller canceled the transaction. After a week, I was still not seeing my payment refunded to my account so I called XXXX. The XXXX representative told me to try canceling the transaction my self because there was no option to request a dispute. I cancelled the transaction on my end and after another week, there was still no refund. The next XXXX representative told me to file a dispute with Discover, which I did on XX/XX/2020. I filed the dispute and uploaded a document for the dispute that I tried to cancel it but it could not cancel because the refund process failed, discover removed the charge from my account pending the decision of the investigation. Since the seller canceled the transaction, they never did send me the device that I paid for. 
After a month or so Discover put the charge back on my account and and sent me an email stating the investigation was found in favor of the seller, attached was a file that had the XXXX ad and a statement from the seller stating the problem was with XXXX and I should call XXXX. I called to complain on XX/XX/2020 and they took the charge back off until they performed another investigation. Once again after a month, they reapplied the charge to my account and sent the same email with the same attachment. Once again I called to complain on XX/XX/2020 so they removed the charge again and continued the investigation. After month Discover once again reapplied the charge to my account and sent the same email and attachment. This time when I called on XX/XX/2020, they stated that the investigation had gone to arbitration and the dispute was found in favor of the seller who cancelled the transaction and never sent me anything because the XXXX ad stated that " Due to the volatile nature of XXXX and the many scammers, there is no returns '', this statement by the seller made them believe the item was shipped to me and I was unhappy with it due to me not uploading more documentation ( which during their investigation I was never asked for more documentation ). 
I have called several time trying to resolve this, but they are completely unwilling to consider the new proof I have uploaded, the only they did was call the seller and 3-way me on the call to talk to him about where the money was, the Discover representative never said a word during this call. I have called XXXX XXXX  many times about this also and was always told they could not tell me anything about this transaction since it was in dispute from Discover, except for the last time when the representative was able to tell me they released the funds to the seller on XX/XX/XXXX when Discover ended their arbitration in favor of the seller, the representative ended the call saying she will send this to their legal department since they released the funds to the seller without proof of shipping the product. Calls to XXXX have been fruitless as well, they show the transaction was cancelled and no refund was issued. I paid for a product that I never received, the transaction was canceled by the seller and Discover, XXXX, and XXXX are not willing to accept the fact that this was a fraudulent transaction.