ってんだ

I'm telling you

→ って
phrase Rare #34,582
I'm telling you A rough, emphatic contraction used to insist on something, often with an angry or frustrated tone. Depending on context, it can also express “what do you expect me to...?” or “what does that matter?”
JA: 何度言わせるってんだ!
EN: How many times do I have to tell you?!

ザマ見ろってんだ

Serves you right!

— TAXi (1998)

だからお前は駄目だってんだ

That’s exactly why you’re no good.

— 生きる (1952)

ここに座れ座れってんだ

Sit down here! I said sit down!

— 預言者 (2009)

でもFBI奴らがどうだってんだ

But the FBI... what the hell do they matter?

— グッドフェローズ (1990)

香港に帰りたいのにどうやって帰れってんだ

I want to go back to Hong Kong, but how the hell am I supposed to get back?!

— ブエノスアイレス (1997)