I believe I see the file you are referring to within your account "converted_file_37ab22c5__1__by_-da3k1pv.wav", however you will see that this file is a .part file. The .part indicates that the file was not completely uploaded. This means that upload process was either stopped prematurely or there was a temporary network issue. In either case, you will not be able to download a file that was not successfully uploaded to the system.
If you had a previous version of this file housed on DriveHQ previously, you will be able to use our file versioning feature to rollback to a past version. Otherwise, you will need to reupload and share the file making sure that the upload process was complete.
Please keep us posted with other questions.