I applied for airdrop but my wallet when import is empty. I had already wrote to support but they are not helping me (they told me that will be back soon with solution, but after few days, not even a voice from them). Looks like that they keep my coins for themself.
click refresh
step 6 in PDF file
http://www.ribbit.me/help/walletrefresh won't help, because if I check on blockexplorer I didn't even get my coins!