I'm having problems as well. Sent over 1500 dollars through zipzap > bitcoin address with three different transactions of 500.00. initially only one of them came through, and i woke up this morning and another 500 was in my blockchain; however i am still missing the last 500. bitinstant support has failed to respond since last night, so i have no way to check the status of the last 500 dollars. I really hope they respond soon.