src/controllers/TinkoffController.php
public function actionBillForm()
    {
        /**
         * @var $bill ShopBill
         */

        if (!$code = \Yii::$app->request->get('code')) {
            throw new Exception('Bill not found');
        }

        if (!$bill = ShopBill::find()->where(['code' => $code])->one()) {
            throw new Exception('Bill not found');
        }

        return $this->render($this->action->id, [
            'model' => $bill,
        ]);

    }
public function actionBillForm()
    {
        /**
         * @var $bill ShopBill
         */

        if (!$code = \Yii::$app->request->get('code')) {
            throw new Exception('Bill not found');
        }

        if (!$bill = ShopBill::find()->where(['code' => $code])->one()) {
            throw new Exception('Bill not found');
        }

        return $this->render($this->action->id, [
            'model' => $bill,
        ]);

    }
Payment form

@throws Exception