Product: Credit card or prepaid card

I am writing today regarding a malfunctioning treadmill costing {$660.00} that I have returned but I have also paid for and unable to get a refund. I made this purchase on my Chase Amazon XXXX card and bought the item on Amazon.com, and neither company is refunding me. I have made multiple calls and emails to both Chase and Amazon.com regarding this issue, totaling hours in my time in XXXX, XXXX, and XX/XX/XXXX. 

The treadmill electrocuted me and I asked to return it, but it was becoming difficult to arrange a pickup for this heavy and bulky item, so I placed a dispute with Chase. Chase claims they sent me a letter asking for support of the dispute but I never received the letter, and for that reason they sided with Amazon and proceeded to rebill me in XXXX XXXX which I have since paid on XX/XX/XXXX - and Amazon has confirmed received the treadmill in XX/XX/XXXX which I have documented in the tracking ID below as well as the attached screenshot of tracking. 

In XXXX, Chase continued to re-assure me that they were working on it. I can prove that I called them many times and spent hours on the phone. On XX/XX/XXXX they sent me a letter that I did receive indicating that the charges for the treadmill were valid. The charge is not valid as Amazon has the merchandise back in XXXX ( nearly 2 months prior to this letter from Chase ) and I do not owe any money for it. 

I, again, spent time on the phone and even got an Amazon representative to speak with a Chase representative to hopefully come to a resolution. They both told me that nothing was possible and Chase said they would contact me after XX/XX/XXXX about reopening the dispute ; both companies said that they could not even touch this issue until then. This date they mentioned has come and gone and they have not contacted me. I asked for the dispute to be reopened with a letter I sent via fax, but to date Chase did not answer my letter. 

Please note order details below : Order Placed : XX/XX/XXXX Amazon.com order number : XXXX Order Total : {$660.00} Shipped on XX/XX/XXXX I returned this item to Amazon in the allotted time. I have confirmed that Amazon received my return on XX/XX/XXXX. 
Please note tracking number and proof of delivery below : XXXX TRACKING NUMBER : XXXX Delivered On : Friday, XX/XX/XXXX at XXXX XXXX at Dock Returned To XXXX, AZ US Received By : AMAZON XXXX Please note proof of the returned item below : Proof of Delivery Dear Customer, This notice serves as proof of delivery for the shipment listed below. 
Tracking Number XXXX Weight 83.00 LBS Service XXXX Ground Shipped / Billed On XX/XX/XXXX Delivered On XX/XX/XXXX XXXX XXXX 
Delivered To XXXX, AZ, US Received By AMAZON XXXX Left At Dock Thank you for giving us this opportunity to serve you. Details are only available for shipments delivered within the last 120 days. Please print for your records if you require this information after 120 days. 
Sincerely, XXXX Tracking results provided by XXXX : XX/XX/XXXX XXXX XXXX EST As per Amazon, they refunded Chase at time of the dispute being opened : XX/XX/XXXX. 
So, at this time : Chase has recharged me {$660.00}, which I paid in XX/XX/XXXX. 
Amazon has their treadmill back I do not have the treadmill and I have paid {$660.00} Chase has delayed me escalating this issue as they promised contact after XX/XX/XXXX, but nothing has happened. 

This charge is not valid as Amazon has the merchandise back and they even emailed me that my credit card should be informed that I do not need to be re-billed. I can provide a copy of these emails from Amazon.

I am owed a refund meaning the recently recharged amount must be reimbursed.