I need to disable (uninstall) this addon as to use the xenforo per default settings. How can i do that?
In the case you're using an Amazon S3 bucket, you can move all the files back using the AWS CLI. Installation guide here: http://docs.aws.amazon.com/cli/latest/userguide/installing.html
Once that's done, run "aws configure" and add your access key and secret key in. Then run "aws s3 sync s3://mybucket ." to download all of the files from the s3 bucket.