Who should handle customer support within an Agile team?

We currently have a maintenance role within our team which the developers on our team rotate each 2 week sprint.

This consists of:

  • Responding to user bug reports & creating stories/issues for them
  • Responding to negative app store reviews
  • Troubleshooting user problems
  • Responding to overall user feedback & feature requests
  • Fixing urgent defects that were not known at the time of sprint planning

Are all of these tasks within a developers domain or are some of these Product Owner or Scrum master responsibilities?