Xbox G Set DLC , 3-Month Subscription Deal Through Xbox Live Dashboard

Per the terms of the offer, you should receive the code by 12/31/2018.

Seriously, this was the deal, why do I have to be doing this?
www.hotukdeals.com/.../50-off-3-months-xbox-live-gold-subscription-800-points-7-50-xbox-live-dashboard-933919

I saw the offer on dashboard however when I went through with the purchase the offer changed to free play days. The offer was buy a year of gold and receive rainbow 6 seige free, there was also something about a deal for the 3 month and 6 month subscriptions.
I'm sorry I don't have a screenshot of the deal as I said it changed immediately after purchase of the year subscription.

Thanks for the update on that. We took a closer look into this and in this particular case, we're afraid we weren't able to find anything on our end in order to confirm that promotion being active.

However, if this is something you saw on the Xbox One dashboard and you followed through with steps to purchase 12-months of Xbox Live Gold through that dashboard offer portal, typically the benchmark for a code to be sent to your account via Xbox Live messaging
would be 7-10 days from the date of purchase.

We recommend waiting that time frame to see if you receive a message from Xbox Live regarding the offer you saw.

I purchased the Xbox Live Gold subscription through the Xbox Dashboard advertisement, I guess in the fine print it must have said it had to be a 3 month subscription somewhere but it took me to a page to choose from either the 3, 6, or 12 month subscription.
Since the advertisement on the dashboard had said you get a free copy of Rocket League with the purchase of an xbox live gold membership, I guess I had thought there wouldn't be a limiting factor to where i had to buy the 3 month subscription to get the game.
Through the advertisement there was no indication that it had to be the 3 month when i got to the purchase screen, so like i said, i guess i assumed i could get the 12 month and everything would be okay. Thank you for your time and clarification!

I saw the offer on dashboard however when I went through with the purchase the offer changed to free play days. The offer was buy a year of gold and receive rainbow 6 seige free, there was also something about a deal for the 3 month and 6 month subscriptions.
I'm sorry I don't have a screenshot of the deal as I said it changed immediately after purchase of the year subscription.