add contact us footer

Author: Renat0Ribeir0

content/Software Support/Upload/Fix-port-access-on-Linux.md

@@ -149,3 +149,7 @@ Another cause of errors are other processes that are using the port.
    ```
 
 7. Try uploading your sketch again.
+
+## Still need help?
+
+If you still need help using your Arduino board, [contact us](https://www.arduino.cc/en/contact-us/).