No, a bitcoin transaction which has already been broadcast to the network cannot be reversed. This is an important feature of the bitcoin protocol which prevents payment fraud.
If you accidentally send your bitcoin to an address being used by a BitPay merchant which you've already paid, please contact our support team at email@example.com.
If you have sent your bitcoin to any address not associated to BitPay or a BitPay merchant, there is nothing that BitPay can do to recover your payment for you. Please contact the person or business you paid if you need to request a refund or return of a mistaken payment.
You can search and view your wallet's transactions by transaction ID or bitcoin address on a block explorer like BitPay's Insight.