That is something you would need to contact a security service about. We can only tell you; 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. ------------ Contact ALL credit cards and banks and have your accounts numbers changed. All you need to do is report what happened. Change immediately ALL passwords on all websites. Also, verify your contact information is correct / not been altered.