Dear sir, please i need clarification about this i paid for american visa fee at GTB i try to book the appointment date i could not fine the actual date i want i decided to leave and after 2 days i logging again to complete the booking the next i saw at the end is conformation meanwhile i have not chosen any date yet, please what should i do? because one agent told me that i can not book with that receipts number again that it has entered into mailbox, i need advise on how to get it done thank you.