Sorry that you have had this problem - your audio won't have been deleted, but VideoScribe may be having some problems with accessing the files. Could you let us know which version of VideoScribe you had before upgrading, and which version you have now? We will then be able to work on getting this resolved for you.
What I would recommend you do is save the scribes with the missing audio to your online directory (cloud icon). When you have done this, load the scribe from the cloud and see if the audio is there. If it isn't let us know the names of the scribes and we can take a look for you.
Sorry for the delayed response. I have saved a copy of your scribe to your online directory with the voiceover attached. I was able to extract the audio from the scribe you saved to your online directory. The name of the scribe on your online directory is 'Sparkol Tripwire Intro Video'. If you have any more similar scribes and would like the audio recovered, please submit a support ticket with the names of the scribes that are saved to your online directory.