diff --git a/playstore/validator.go b/playstore/validator.go
index d56490d..5f0d6ae 100644
--- a/playstore/validator.go
+++ b/playstore/validator.go
@@ -11,8 +11,6 @@ import (
 )
 
 const (
-	scope = "https://www.googleapis.com/auth/androidpublisher"
-
 	defaultTimeout = time.Second * 5
 )
 
@@ -42,12 +40,12 @@ func New(jsonKey []byte) (Client, error) {
 		Timeout: timeout,
 	})
 
-	conf, err := google.JWTConfigFromJSON(jsonKey, scope)
+	conf, err := google.JWTConfigFromJSON(jsonKey, androidpublisher.AndroidpublisherScope)
 
 	return Client{conf.Client(ctx)}, err
 }
 
-// VerifySubscription Verifies subscription status
+// VerifySubscription verifies subscription status
 func (c *Client) VerifySubscription(
 	packageName string,
 	subscriptionID string,
@@ -64,7 +62,7 @@ func (c *Client) VerifySubscription(
 	return result, err
 }
 
-// VerifyProduct Verifies product status
+// VerifyProduct verifies product status
 func (c *Client) VerifyProduct(
 	packageName string,
 	productID string,
@@ -80,3 +78,29 @@ func (c *Client) VerifyProduct(
 
 	return result, err
 }
+
+// CancelSubscription cancels a user's subscription purchase.
+func (c *Client) CancelSubscription(packageName string, subscriptionID string, token string) error {
+	service, err := androidpublisher.New(c.httpClient)
+	if err != nil {
+		return err
+	}
+
+	ps := androidpublisher.NewPurchasesSubscriptionsService(service)
+	err = ps.Cancel(packageName, subscriptionID, token).Do()
+
+	return err
+}
+
+// RefundSubscription refunds a user's subscription purchase.
+func (c *Client) RefundSubscription(packageName string, subscriptionID string, token string) error {
+	service, err := androidpublisher.New(c.httpClient)
+	if err != nil {
+		return err
+	}
+
+	ps := androidpublisher.NewPurchasesSubscriptionsService(service)
+	err = ps.Refund(packageName, subscriptionID, token).Do()
+
+	return err
+}
diff --git a/playstore/validator_test.go b/playstore/validator_test.go
index f33dba9..86afee0 100644
--- a/playstore/validator_test.go
+++ b/playstore/validator_test.go
@@ -104,3 +104,47 @@ func TestVerifyProductAndroidPublisherError(t *testing.T) {
 		t.Errorf("got %v\nwant %v", actual, expected)
 	}
 }
+
+func TestCancelSubscription(t *testing.T) {
+	// Exception scenario
+	client := Client{nil}
+	expected := errors.New("client is nil")
+	actual := client.CancelSubscription("package", "productID", "purchaseToken")
+
+	if !reflect.DeepEqual(actual, expected) {
+		t.Errorf("got %v\nwant %v", actual, expected)
+	}
+
+	jsonKey, _ := json.Marshal(testJSON)
+	client, _ = New(jsonKey)
+	expectedStr := "Post https://www.googleapis.com/androidpublisher/v2/applications/package/purchases/subscriptions/productID/tokens/purchaseToken:cancel?alt=json: oauth2: cannot fetch token: 400 Bad Request\nResponse: {\n  \"error\" : \"invalid_grant\"\n}"
+	actual = client.CancelSubscription("package", "productID", "purchaseToken")
+
+	if actual.Error() != expectedStr {
+		t.Errorf("got %v\nwant %v", actual, expectedStr)
+	}
+
+	// TODO Normal scenario
+}
+
+func TestRefundSubscription(t *testing.T) {
+	// Exception scenario
+	client := Client{nil}
+	expected := errors.New("client is nil")
+	actual := client.RefundSubscription("package", "productID", "purchaseToken")
+
+	if !reflect.DeepEqual(actual, expected) {
+		t.Errorf("got %v\nwant %v", actual, expected)
+	}
+
+	jsonKey, _ := json.Marshal(testJSON)
+	client, _ = New(jsonKey)
+	expectedStr := "Post https://www.googleapis.com/androidpublisher/v2/applications/package/purchases/subscriptions/productID/tokens/purchaseToken:refund?alt=json: oauth2: cannot fetch token: 400 Bad Request\nResponse: {\n  \"error\" : \"invalid_grant\"\n}"
+	actual = client.RefundSubscription("package", "productID", "purchaseToken")
+
+	if actual.Error() != expectedStr {
+		t.Errorf("got %v\nwant %v", actual, expectedStr)
+	}
+
+	// TODO Normal scenario
+}