I asked for a UA Platinum challenge on 19th Nov and on 22nd Nov they replied me with an approval of gold like this:

"Congratulations! You have been awarded a trial period of Premier® Gold status in the MileagePlus® program valid until 03/01/2015! This will make your travel with us comfortable, simple and more rewarding than ever.
To remain a Premier Gold member through January 31, 2016, you will need to fly 12,500 Premier qualifying miles (PQM) or 15 Premier qualifying segments (PQS) on flights operated by United®, United Express® or Copa between 12/01/2014 through 03/01/2015.*

But after several days, when I emailed UA Mileageplus department to ask about when my account would be changed into Gold status (because I booked UA flights and wanted to choose seats). I got a reply like this:

"We are unable to confirm that your will become a premier Gold member in December 1, 2014 since there is no record showing this information in your account. "

I am so confused and email them again but I still haven't got any reply from UA for several days. I called but the CS replied the same information.

Anyone experience this? Today is 1st Dec and my account has not been changed. What should I do next?

Thanks in advance!