There isn't a way to restore a record in Xero/Quickbooks once it has been deleted.
1. Remove The Payment In BriteBiz
As you deleted a payment in Xero/Quickbooks, you need to remove the payment from BriteBiz. You do not need to do this manually as the integration will do it (which it does overnight or you will probably want to do it straight away).
So - simply click the Xero/Quickbooks icon (top right corner) on the payment page (CLICK HERE). This will sync any recently updated payment and should remove this payment from the booking in BriteBiz.
2. Record The Payment Again
Once you have this done, simply record the payment again in BriteBiz which will mean you have the payment recorded in BriteBiz and Xero/Quickbooks.