This could occur in the case where either the transaction dropped and couldn’t be completed or the destination tag added on the Ripple transfer was incorrect/not recognised.
Please raise a support ticket letting us know of the issue and if the transaction dropped then we can re-initiate the withdrawal 48 hours from the original withdrawal time.
In case, the destination tag was incorrect/not recognised, then you must mention the correct destination tag in the support ticket and we will re-initiate the transfer 48 hours after we receive the required information.