Technical issue with Xbox store missed promo

I was attempting to purchase Diablo 3 eternal collection on the xbox store 2 days ago for the promotional price of 19.99 and it kept giving me a technical error and told me to attempt to purchase this item at another time. I kept trying and by the time
i realized it was working i ran out of time for this countdown promotion. Im furious and customer service on the phone gave me the run around and said the only thing i can do is post here and hope someone helps. This is such poor customer service ans i shouldnt
have to sit ans wait for a person to respond on a public forum about technical issues.

:)