Zero-confirmation transactions are inherently unsafe to be considered as completed payments. It is not possible to create a tool that could give a truly reliable indication of whether or not an unconfirmed transaction will in fact confirm (or not). If it were possible to reliably predict such a thing, we wouldn't need a blockchain record in the first place.


In this case, you would need to contact the ATM operator / service provider, and provide them with some proof of your purchase and the failed transaction. When completing your interaction with the ATM, you should receive some sort of receipt that details this information, though the exact specifics will likely vary from one ATM to another. If you are running ...


It's generally not possible to cancel BTC transactions after they are broadcast to the network. If the transaction is valid, it can be held by miners until it's economically interesting for them to confirm the transaction (until there are no other transactions paying higher fees). When you say "double spending", you are probably referring to a ...

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