Unable to withdraw

After one day of previous two successful withdrawals of 100USD, the third time is to withdraw 700USD, but failed to withdraw successfully. The withdrawal time applied for last Thursday annd it was promised to withdraw within 24 working hours. It has been a few days, but I have not seen any successful withdrawals. I have contacted customer service many times and kept ask me to wait for updates. Other than that, there is no explanation, which makes people angry.