Globalautomotive of Miami Refused to honor warranty or issue refund as agreed. Miami Florida

I purchased a fuel pump on eBay from this seller it failed just after 30 days from receipt and installation.  This seller refused initially to honor the warranty.  Then told me the forms were sent and that they must be going to my junk mail.  Then told me by was not eligible for the Warranty option.  I was then contacted by the seller and offered a full refund if only I changed my negative rating on the eBay, which foolishly I did. No refund has been made at this time and the Seller is now unreachable.