You probably downloaded your backup before you canceled your account and it didn’t include the uploads.
You might ask again very nicely if they can temporarily restore the uploads to S3. I had this happen a while back when they got around the cleaning out their old S3 buckets and they were able to restore the uploads to S3 for a bit.
If they can, you can then contrive to download those images from S3 and then re-upload them to your own S3 bucket, or otherwise contrive to get them into discourse. It’s something of a chore, but it is possible.