This is likely because although it is not showing on your banking statement, it is still present on your banking feed. Once this disappears from your banking feed, it will be automatically removed.
It can take up to five working days for pending transactions to be removed.
If the pending transaction is still present after this time, please let our support team know who can look into this for you.
You can get in touch with our support team by selecting Settings, then Support and Contact Support.