The unfortunate answer is: with great difficulty. As we have previously mentioned, it is estimated that billions of dollars of Bitcoin is lost. Unless you know the person whom you mistakenly transacted with, the chances of your BTC returning to you are slim. That is one of the big dangers of a paper key: while it is offline, and therefore protected from hackers, it is far from safe and may be lost or stolen. Furthermore, it is important that users back up their Bitcoin wallets as Bitcoin has no access to nor any control over users' wallets or their private keys. As Bitcoin.com support notes: "If you were to lose or break your device, the only way to recover your Bitcoin.com wallet and the funds held within is with your 12-word backup phrase."