You should whitelist firstname.lastname@example.org in your Kindle account to be able to receive deliveries. This was already explained in setup steps when you created your first delivery. If you skipped this step for some reason, click here to go to your Amazon Kindle account and under the "Preferences" tab, click on "Personal Document Settings". Then find "Approved Personal Document E-mail List" section and add this email address: email@example.com
You cannot change delivery email for an existing delivery. When you create a new delivery (delete the old one if you wish), you will have an option to change your delivery email on the popup that comes before the last step.
You cannot send all your articles with a single delivery because Amazon puts 25MB limit on deliveries, so we cannot bypass that. 20 article limit is put to ensure you receive your deliveries reliably. Multiple recurring deliveries can help you do this easily. If you want all articles in your Kindle right now, you will need to create multiple onetime deliveries. Signing up for a premium/platinum account can speed this up for you and ensure you receive all of your deliveries right away.
If you feel your Kindle is cluttered with articles and you would like to delete your articles from your library completely (not only from your device) you can go to Manage Your Content and Devices page on Kindle and after logging in, go to Content tab. Then on the left side where it says Show: Books, you can change that filter to show Docs. At this point you should be able to see all your P2K deliveries (Author column will be marked as p2k.co), select as many as you would like to delete and they won't show up in your library anymore. P2K does not provide Kindle support, if these instructions don't work for your device, then please contact Amazon.
Simply go to your Kindle settings and open Settings tab. Then go to section "Personal Document Archiving" and turn archiving off.