Since blockchain transactions are irreversible, Slush cannot cancel the transaction or recover funds sent to the wrong address or network. If your transaction did not arrive at the desired address, first verify the transaction on a Sui explorer like suiscan.xyz. If you don't have access to the recipient's wallet address, the funds cannot be recovered.
Always double-check the recipient's address before submitting any transaction. If you're still unsure, submit a support ticket directly in the app for assistance.