If the process of payment has been interrupted, but you only uploaded files to iCloud and did not keep the originals on your device, the files were gone.
You can follow the below steps to recover your lost files on iCloud.
Step 1: Connect your iPhone to your Mac running macOS Catalina or later.
Step 2: Open Finder and then select your device under the Location list.
Step 3: Click Restore Backup.
Step 4: Choose the latest date of backup and click Restore.
Step 5: Type in the password if requested and wait for the restore to finish.
Up to now, you can restore your lost files on iCloud.