When you place an order, an authorisation hold is put on your credit card for the value of your order. This secures the funds but does not take the funds as these are not taken until your order is dispatched.
If your order is cancelled for any reason, UNIQLO will send an authorisation reversal to your bank.
The exact amount of time until the hold is removed from your account is determined by your bank or credit card company, so the time frame may vary. Should payment not be released with 30 days (from when the transaction took place), please do contact the bank or credit card company.