Unfortunately PayPal does have limitations with only 20% increase in pricing allowed (to avoid fraud).
The best workaround is to cancel your current subscription on the Settings page (keyhole.co/users/settings), and then re-subscribe to the Corporate plan using the payment option directly on our site. As long as you do this immediate after cancelling, your trackers shouldn't lose any data.
To ensure this is the case, visit the My Tracks page to resume any paused trackers immediately after upgrading, so that you don't lose any data. Please contact us at firstname.lastname@example.org or file a support ticket above if you run into any issues.