Please follow the steps below and make sure you have filled in the form here: http://kshelper.evebot.cc/#/
Here is a video that shows you how to get more than one printpen by adjusting your pledge: https://youtu.be/Ak8SWlMeIoo, according to your pledge amount, we’ll know how many printpens you pledged.
Here is a guide from Kickstarter: “To change your pledge amount, visit the project page and click the “Manage your pledge" button that appears next to your pledge amount and then select "Change your pledge". From here, you’ll be able to adjust your pledge amount or choose a new reward tier you'd like to pledge for and your pledge amount will update automatically.
The amount you enter will be the total amount collected if the project is successfully funded.” You can also check here: https://www.kickstarter.com/help/search?utf8=%E2%9C%93&term=Can+I+change+my+pledge%3F