Support
Most problems are one of the five below. If yours is not, write and say what happened.
Check it is still a zip. If your Mac or phone unzipped it automatically, zip the folder back up, or download the archive again and choose Save to Files rather than opening it.
HIT looks for .fit, .gpx and .tcx files anywhere
inside the archive. If there are none, there is nothing it can import.
Those are listed at the end of the run under Summary only. It means the track file for that activity would not parse, so the activity was imported from its summary row instead. The workout, its date, duration and distance are all there; the per-second detail is not.
Apple only lets an app delete data it wrote itself, so a workout recorded by your watch or another app cannot be replaced by HIT. It can add the heart rate, cadence and power that are missing, and it will offer to.
Energy and distance are deliberately not added, because Health sums those across sources and adding them would inflate your Move ring. If you want the fuller copy, delete the original in the Health app and run HIT again.
Open HIT again. It offers to carry on from where it stopped, and picking that up costs one check against Health rather than reading every file a second time. Nothing is written twice.
Imports pause when you switch to another app, because iOS suspends the work. Staying in HIT while a long import runs is the only requirement.
Open the unlock screen and press Restore purchase. Purchases are tied to your Apple Account, so make sure you are signed in with the same one you bought with.
Refunds are handled by Apple, at reportaproblem.apple.com.
Write to support@enalmar.uk and say what you did, what you expected, and what happened instead. If HIT showed a number, it helps to include it.