Learn Hardcore Korean: dapjangeul mos badassdamyeon jigeum bonae jwo. - If you haven’t gotten a reply, send it now.

Korean drops subjects when they’re clear from context. In 답장을 못 받았다면, the subject is unspecified; the command 보내 줘 (“send it to me”) only tells us the listener is the one who must send. Context decides whose not-receiving is intended.

If the speaker hasn’t received it: 내가 답장을 못 받았다면, (나한테) 지금 보내 줘.
If the listener hasn’t received one: 네가 답장을 못 받았다면, (나에게) 지금 보내 줘. Tip: 네가 is written “네가” but commonly pronounced “니가.”

Why is it 답장을 (object marker) instead of 답장이 (subject marker)?

Because 받다 (“to receive”) takes a direct object. You receive a reply, so 답장 takes -을/를: 답장을 받다. Using 답장이 would make it the subject and doesn’t fit this verb pattern here. (You can use 답장은… as a contrastive topic in some sentences, but not in this verb-object slot.)

What nuance does -다면 have compared with -면/-으면?

-면/-으면 is the default “if/when.”
-다면 adds a slightly more hypothetical, “if it turns out that…” feel, often used when the speaker is entertaining a condition as an assumption or outcome they’re checking. Here, both are fine: 못 받았으면 and 못 받았다면. The -다면 version feels a touch more “suppositional.”

Why is the verb in the past (받았다면) when the idea is “if you haven’t received (yet)”?

Korean often uses past inside a conditional to mean a resulting state up to now (“if it’s the case that you have/haven’t received”). So 못 받았다면 ≈ “if you haven’t received.”
If you say 못 받으면, it leans toward a future or general condition (“if you don’t receive [whenever/going forward]”).

Should I add 아직 (“yet”)?

Optional, but natural: 아직 답장을 못 받았다면, 지금 보내 줘.
아직 makes the “not yet” nuance explicit. Without it, context usually supplies that meaning.

Why 못 and not 안? What about 받지 못했다면?

못 = couldn’t/didn’t manage to (lack of ability/opportunity), the natural choice for not receiving a reply.
안 = deliberately didn’t; 안 받았다면 can sound like you chose not to receive it.
받지 못했다면 is a more formal/explicit version of 못 받았다면. All are grammatical; 못 is most idiomatic here.

What does 줘 add in 보내 줘?

줘 is the contracted 주어 from 주다 (“to give”) used as a benefactive auxiliary: “do X for me.”

보내 = a blunt imperative “send.”
보내 줘 = “send it (for me), please,” softer and more natural.
To be polite: 보내 주세요, even softer 보내 주시겠어요?, 보내 주실 수 있을까요?

Is it 보내 줘 or 보내줘 (spacing)?

Standard spacing prefers separate: 보내 줘 / 보내 주세요 (auxiliary verbs written separately). In everyday writing you’ll also see 보내줘 / 보내주세요; both are widely accepted informally. In careful writing, keep it separate.

Do I need to say “to me,” like 나한테/저한테?

Not required; 줘 often implies “for me.” Add it for clarity or contrast:

Casual: 지금 나한테 보내 줘.
Polite: 지금 저한테 보내 주세요. You can also specify someone else: 민수한테 보내 줘 (“send it to Minsu for me”).

Is this too casual? How do I make it polite or softer?

보내 줘 is intimate/casual. Politer options:

답장을 못 받았다면 지금 보내 주세요.
Softer: …지금 보내 주실 수 있을까요?, …지금 보내 주시겠어요? Add 좀 for extra softness: 지금 좀 보내 주세요.

Could I say 못 받았거든 지금 보내 줘?

Yes. -거든 in spoken Korean often means “if/when that’s the case, then…,” and can sound a bit more directive/casual: 답장을 못 받았거든 지금 보내 줘. It’s fine in friendly speech.

Where should 지금 go? Can I put it at the start?

Best right before the verb it modifies: …지금 보내 줘.
You can front it: 지금, 답장을 못 받았다면, 보내 줘, but that can sound marked. Avoid placing 지금 so it seems to modify 못 받았다면 unless that’s your intention.

Is 답장 the right word, or should it be 답변/회신?

답장: a reply in personal communication (texts, DMs, letters).
답변: an answer to a question (Q&A, interviews).
회신: a formal/business reply.
This sentence fits 답장 best.

Could I say 받았으면 instead of 받았다면?

Yes. 못 받았으면 지금 보내 줘 is extremely common and neutral. 못 받았다면 sounds a bit more “if it turns out that…,” but in everyday speech both are fine.