Pro Tip: Click here to send the seller of your item a message and dispute a charge. If this doesn't work, then log in to your Amazon Pay account and click on 'File/View Claim' under your product's details.
To dispute a charge on Amazon it's advised that you speaking with your merchant first. Check 'Your orders' and look at the details of your order. it includes your merchant's contact details. Contacting the seller of your product is the best way to sort out issues with your charges because Amazon.com isn't able to fix certain issues.
Amazon won't be able to decrease charges on a product if it's from a third-party-seller. However, if you aren't able to dispute a claim with a merchant, then Amazon Pay does provide another way for you to make a dispute.