The call on line 659 of Paystack.php for transaction not found should be,
throw new PaystackExceptionApiException(
"Paystack Request failed with Response: '" .
$this->messageFromApiJson($resp)."'",
$resp
);
and not
throw new ApiException(
"Paystack Request failed with Response: '" .
$this->messageFromApiJson($resp)."'",
$resp
);