To cancel a pending transaction on Coinbase, log in to Coinbase.1-(855)(288)(0231) using a web browser (not the mobile app). ＋1-(855)(288)(0231) Select the asset with the pending transaction, find the transaction, and choose Cancel payment. ＋1-(855)(288)(0231)  If this option isn’t available or the transaction is confirmed on the blockchain, cancellation isn’t possible.＋1-(855)(288)(0231)  For issues, contact Coinbase support directly.