For Drupal core and all Drupal contributed modules there is an issue queue, which you can use to request support or provide feedback. This is the most reliable way of communicating with the maintainers of the modules in question.
Remember, those individuals looking after different modules have assumed the responsibility of responding to questions in the issue queues, but they are still volunteers. Some more popular modules generate more questions than it would be possible to process as a full-time job.
If you want to communicate with the module maintainer or Drupal core team, create a new issue using the project page.
In order to get attention for your issue, be as clear and descriptive as possible. If you are reporting a bug, provide the steps to reproduce it.
The best practice for getting help in the Drupal issue queues is as follows: