If you are using getInstance
then you must access the payment instance by using $merchant->payment->
else if you are working with getPaymentInstance
you can directly call the payment class method.
Initialize payment from backend
$result = $payment->initialize(['array']);
if($result->isSuccess()){
//Do something
}
Charge customer card
$result = $payment->charge(['array']);
if($result->isSuccess()){
//Do something
}
Charge customer card authorization code
$result = $payment->chargeAuthorization(['array']);
if($result->isSuccess()){
//Do something
}
verify payment with transaction reference number
$result = $payment->verify($reference);
if($result->isSuccess()){
//Do something
}