The process of decentralized blockchain technologies moves one way. This means that blockchain technologies are immutable and the data saved cannot be changed or manipulated. If you do any transaction on a decentralized app and the transaction is successful, it can not be reversed or canceled. Thus, if a transaction shows a confirmed status, then the transaction is final and has been added to the next blog.  

A transaction can only be canceled if it is still pending. 

If a transaction has been processed and completed, it can not be reverted by anyone. 

The only troubleshooting the user can do is check with the receiver or the receiving app, and see if they can do anything from their end. (We mean if they can refund your funds through a new transaction.