safari using old address

My old address keeps getting autofilled in Safari. People have asked this question before in these threads, but it appears that every time a bunch of unintelligent people comment something like "cHecK yoUr CoNtaCt caRd and maKe SuRe iT Is RiiiigHtuhtuhtuh"... which obviously helps no one... and then the thread goes stale. Can anyone provide definitive step-by-step instructions on how to make sure autofill ONLY fills what is in my contact card? And nothing else?

Do not guess if you just want to feel intelligent.

Apple support - I am never using Safari again if this can not be easily figured out