How do I contact a human at Mozilla Firefox ?

You are doing it. Your iPad used to be normal, right? https://support.mozilla.org/en-US/kb/install-firefox-your-ipad-iphone-or-ipod What's your iOS version?

version 153(?) my iPad does work fine. It’s the Firefox app which doesn’t look or work the same. Can’t find/get tool bar, can’t customize which control buttons to add, doesn’t env have the Firefox icon at the top. Something called defendervault.shop claiming to be a Norton thing, keeps popping on….

How do I contact a human at Mozilla

There are only humans. And a few pets, too, right! You can check mozilla.org/contact if there's anything that you prefer, incl. social accounts and the like. Do you have anyone particular in mind? Most of the teams work in the open and are available e.g. on wiki.mozilla.org/Matrix or other discussion platforms.

Using iPad. Can’t find toolbar, can’t customize, ads interfering, everything looks totally different.

That sounds right, iPadOS runs a completely different web engine, so the iOS version of Firefox is custom to work on the Apple platforms. Are you saying that you had iPad version of Firefox earlier that did all of the above?