If you've reinstalled Stitched Off or moved to a new device, open Settings ▸ Stitched Off Pro in the app and tap Restore purchases. Or sign in with the account you bought Pro with, and it's there. See Manage your subscription.
My chart read wrongly. What now?+−
Every read is shown to you in the setup steps before you stitch, and you can fix it there: tap a grid's four corners or set its size, and correct any thread in the legend by hand. See Fix a grid and Fix the legend. If it still won't read, tell us — there's no need to send the chart.
How do I back up?+−
With sync on, your patterns and progress are kept in your Stitched Off account as you go. You can also back up any pattern as a single file and keep it wherever you like. See Back up a pattern.