Just trying to make sure, but does it say "Thanks for various help?"

I would have never guessed to say that.

That is correct, and your own response was by far the best until freel4ncer posted his, too.

In many real-life situations, the key to sucessfully saying "Thank you" in Japanese is to not say ありがとう.

何でもする bit does not make sense.
You should use いろいろお世話になりました。Thank you is then implied.

I see. But one more thing. Can you please explain why なりました is used here?

I've always thought it means "to become" or "to be" or something of that nature.

お世話になる is a set phrase/idiom meaning for someone to take care of you. It's a bit like 薬を飲む. Nobody drinks medicine but it's just the way it is in Japanese.

Also idioms are language specific and don't translate (obvoiusly).

OHHHHHH okay I understand. Thanks a lot, kirakira.

I think these phrase/idioms is what is making Japanese difficult sometimes for me. Cause like...how would I ever know to say "drink medicine"

Thanks kirakira!