Bitcoin Transactions are not reversible

Posted by Bitcoin Basics

Just as with cash, when Bitcoins are sent from one person to another, the transaction is permanent.

Bitcoin doesn't have any chargebacks. Once you've received bitcoin, it is yours to keep, there is no outside agency that might take it away.

Many Bitcoin On-Line retailers have lower prices or give a discount for paying with bitcoin because they know that these transactions aren't at risk of being lost