I just left the change at the store.

Thank you♥

Left it on accident or decided not to take it?

The latter I think.

Yeah, I just read the “incident report” in another post. She didn’t take the change. Viktoria’s translation is correct.

Ага, я как-то не подумала, что left может означать «забыла».)

Да))

BTW, in this context, could I also reply with Да уж, and what would it imply?

Not really. You can use it when
(1) someone is unhappy with the way things are and you agree with them.
- Когда уже эта пандемия закончится? Никакой жизни - год дома в заточении сидим.
- Да уж. Достала эта корона.
(2) when you're skeptic about some statement. - Говорят, скоро конец пандемии, и границы скоро откроют.
- Да уж. Сколько раз их уже «открывали» - одни обещания и только.
(3) when you disapprove what someone did.
- Папа, я опять экзамен завалил.
- Да уж, нечего сказать. Заниматься надо, а не с друзьями тусоваться день и ночь.
What's common that it's always sort of "sad".

-- When's this pandemic going to be over with already? This is no life - a prisoner in your own home.
-- Tell me about it/I mean really. I've had it with this coronavirus.

-- They say the pandemic will be ending soon and the borders are going to open back up.
-- Yeah right. How many times does that make that they've "opened them" - promises, promises.

-- Daddy, I failed another test.
-- Yeah well... what's there to say. You need to hit the books more and not hang out with your friends day and night.

Thank you!

And what if I answered а вот и да

А вот и да sounds like something you say if you agree with the speaker, after someone else replied А вот и нет! to them.
Зина: Выходцы с Кубы могут быть зеленоглазыми.
Нина: А вот и нет! Они все кареглазые.
Uly: А вот и да!....

Aha, that brings me to my next question: what exactly does a вот и нет mean/imply?

Zina: Some Cubans have green eyes.
Nina: Oh no they don’t! They all have brown eyes.
Uly: Oh yes they do! I have green eyes.

А вот и emphasizes anything that goes after it, be it a negation or an absolute disagreement.
https://ru.m.wiktionary.org/wiki/%D0%B0_%D0%B2%D0%BE%D1%82_%D0%B8

Ah, ok. Thank you)))

Спасибо тебе за перевод моих примеров! 😉🙏

Going back to your initial question, you could use Да уж as a reply to
Ага, я как-то не подумала, что left может означать «забыла».) in the meaning of
Да уж, вечно ты всё забываешь/ты что-нибудь да забудешь. 😜