How to get data back after a phone reset

Did you sync data to iCloud? If so you can recover anything that you synced. Other than that, without a backup you must start over as if it was a new phone.

Are you sure you never enabled automatic iCloud backups, or synced to your computer?

As mentioned, if you didn’t do a backup prior to the repair or have access to a recent backup (perhaps via iCloud) you can’t recover any missing data not available elsewhere.

Sorry, no backup, no restore.