Unfortunately Stamped.io requires you to contact them to get a full export of your own data. We've been told from a number of merchants that this process isn't straight forward & often Stamped tries to make it quite difficult in an attempt to convince you to stay.
This doc from Stamped shares how to export smaller segments of data: https://help.stamped.io/article/238-review-exporting-reviews-checkout-comments
To export all your data & migrate to Junip without contacting their team, simply export to different filtered views from Stamped (so two total files) and then upload both of those to Junip. The example we like to use is:
First file: Show all where > photos is > without photos
Second file: Show all where > photos is > with photos
Once you've exported your two files, you can import them into Junip
We "dedupe" reviews on import, so you don't have to worry about accidentally importing the same review from Stamped twice. Welcome to Junip!