Confirmed transactions are irreversible. This is the nature of all blockchains.


BITCOIN

If you have an unconfirmed BTC transaction, it's not possible to cancel or replace it. You may be able to make it confirm faster. You can read tips here.


ETHEREUM

You can replace an unconfirmed Ethereum transaction that you sent from Coinomi with a higher fee, so that it confirms, or you can cancel it altogether, so that the funds never leave your wallet. 


Note: In Ethereum, transactions must confirm IN ORDER. That means that if you have many pending transactions, you must start by canceling or replacing the OLDEST one first.


To do so,

  1. Open https://etherscan.io and use the search bar at the top to search for your own Ethereum address.

  2. Scroll down and look at the list of transactions

  3. Find the "nonce" value of the transaction that you want to replace
    • If you can find the unconfirmed transaction on the list, open it, press the button "click to see more" to expand the details of the transaction and note its "nonce" value. The number 6 on the image below is just an example.
      Then proceed to step 4 below

    • If the unconfirmed transaction isn't listed on Etherscan, open the last outgoing transaction that is confirmed (check both the regular as well as token transactions). Look at its "nonce" value and add 1 to it (for example, if you see the highest confirmed outgoing nonce is "7", note the number "8"). If you have no confirmed outgoing ETH nor token transactions, use the value 0 (zero).

  4. Go to your Coinomi Ethereum wallet from which you sent the unconfirmed transaction.
    • TO REPLACE A TRANSACTION: Go to the "send" section and enter the same destination address and same value as the unconfirmed transaction that you are replacing.
    • TO CANCEL A TRANSACTION: Go to the "receive" section and copy your own address. Then go to the "send" section, and send 0 ETH (you have to type the number 0 in the amount field) to your own Coinomi Ethereum address that you copied before.

  5. Before you click "Next", click on the "advanced settings" and enter the nonce number that you found on step 4 at the "nonce" field. Touch NOTHING ELSE from the advanced settings. The number 6 on the image below is just an example.

  6. Continue to the confirmation screen. You will see 4 options: Select the "High" (Priority) fee option and send your transaction normally.

  7. After the new transaction confirms, at the top right corner of your ETH wallet select "... / Resynchronize" once to force a refresh of your transactions and clear the replaced ones.

  8. You're done. This new transaction will replace your pending transaction with the same nonce. On the block explorer canceled transactions have a status of "Dropped and Replaced" as in the image below