Woah, no, no just "forgetting" keys. There's a reason why Russian has those letters - because they're, you know, part of the language. That's like saying "The F key isn't showing up, so let's just skip that one. No one uses F when speaking anyway, right?"

Not sure why the letters aren't displaying either, there's many places where that could go wrong, but "ф/Ф" and "э/Э" ARE integral part of the language in Russian, and it's better to be able to type it with some visual glitches than to not type it at all. Like, there are words you just can't say without those letters, just like you can't type "car" without a "c" or "number" without a "u".

Also try these (first one's lower case, second is upper case) instead:
ф Ф <-- the "ϕ" looks different on my computer and that might be the problem, you might be trying to use the 'Greek' symbol in question, which is actually different than the current standard Russian one, thus having different UTF/ASCII codes, and thus some fonts/systems might ignore the Greek one but not the Russian one.
э Э <--- THESE are the right э in Russian, not "ϵ". Unless you're trying to say е Е or з З, but that doesn't look like it.