XlsxWriter was written by John McNamara.
If you have questions about XlsxWriter here are some ways to deal with them:
See the Reporting Bugs section of the docs.
Open a Feature Request issue on Github issues.
See the Contributing Guide. Note, all Pull Requests must start with an Issue Tracker.
General questions about how to use the module should be asked on
xlsxwriter tag to the question.
Questions on StackOverflow have the advantage of (usually) getting several answers and it also leaves a searchable question for someone else.
If none of the above apply you can contact me at firstname.lastname@example.org.
If you have found XlsxWriter useful, then donations are always welcome.