The code I redeemed is new I bought it few mins ago when I used . But it shows it's...

Hi there,

for information you requested it might be best to contact Xbox Support via Phone.

To contact Xbox Support via Phone see this link for the details:
https://support.xbox.com/contact-us?isChatCallAvailable=false

Let us know the results

Get it in touch with customer support team,

Please contact the xbox support team or the retailer

If you bought the code from a code selling site like G4A, Kinguin or the likes, it might be possible that you got a seller, that tries to scam people, by selling a code multiple times.

Since Microsoft support probably won't provide you with those details for privacy reasons, the seller can continue to scam people, as they have no way to comply with the seller's demand for information. So they will be "Oh, I would like to help you, but
unless you provide me proof that it was redeemed sometimes earlier, I won't be able to help! Thanks for your money."

Therefore do NOT buy codes from dubious code selling sites.

I also do not have the pack even after redeeming a code. I redeemed the code a week ago, bought The Division a few days ago and there is no extra DLC for the Division other than the Hazmat Pack. Agent Origins Pack is not showing up in game either.

the Agent Origins website now says "this offer is expired" so thats alarming...