Can't read Comixology comics purchased on my Kindle Fire since app update
There are a few things you can try before contacting Comixology support.


Go to the Settings of the Comixology app, and then tap the Restore Purchases button. That might solve things if you're logged into your comiXology account.
If that doesn't work, you can go to the Purchases section of the app and Read from there. Click on the Comixology icon in the top left corner of the app to view the menu to switch from Featured, Publishers, Purchases, etc.  Once you're on the Purchases screen, click on a book, then click the Read button.
The final solution to try would be to re-install the Comixology app.