You mean "Contact us"
They got back to you so soon?
I went to: MileagePLus-> Mileage PLus Service Center ->Contact Us (Clicked on "Learn More") ->Email Mileage Plus.
I emailed them yesterday at 8:33 AM with the offer screenshot you had posted on the main site. They responded at 4:32 PM saying that I had not enrolled in the offer. At 4:48 PM Yesterday, I responded with a screenshot of an email confirmation I had saying that I was enrolled. This morning, at 11:39 AM today I emailed them again because I had not heard from them. Then, at 12:52 PM today, I got a response that they were awarding the points.