fixed docs

readme.md

@@ -19,3 +19,12 @@ To make new API credentials, You should make order a Widget on this page: https:
 For tests, you can use these data:
 * App ID = `a63127be-6440-9ecd-8baf-c7d08e379dab`
 * Api secret = `25615105-7be2-4c25-9b4b-2f50e86e2311`
+
+
+
+# Attention!
+
+Keep in mind that if the site in which You are testing payments is not publicly
+accessible for requests from the Internet, then notifications of changes in
+the status of payments from Our processing service will not be able to reach
+Your online store, as a result of which the status of orders in your store will not change.