Is this just with Amazon, or do you think they got into your system? Step one: Change all passwords on anything you suspect has been compromised. Also, check your profile data on all websites to make sure it is correct. You may have ad/mal-ware. Further information can be found in this article; https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-caused-malware?cache=no Run most or all of the listed free to use malware scanners. Each works differently. If one program misses something, another may pick it up.