Bug reports and feature requests (collectively, "issues") are managed through Bitbucket issue trackers.
For general enquiries use the contact page.
Please click the Bitbucket which best applies:
Relating to the Arpeggio program.
Issues concerning erroneous or questionable output and feature requests relating to calculations and methodology.
This website and the calculation interface.
Dead links, mistakes or omissions, FAQ requests, broken stuff. Anything relating to the web interface itself including design.