Voicemail WAV email attachment problems

[Paranoid]

My company uses Cicso Unified Messaging to send an email to our exchange email accounts with each voicemail attached as a WAV file. the Mail app is having problems with the attachments, and these WAV files sometimes show up as a different file, or the attachment doesn't show up at all. I've called Verizon tech support about this, their solution is to delete the email account from the phone and add it back. This works, but only for a few days, then the problem comes back. I use an HTC Droid Eris.

Also, my boss uses a Moto Droid and his voicemail attachments show up as the correct file, but his phone has recently stopped being able to play WAV files. It worked a few weeks ago, but recently it says the WAV is an unsupported file format.

Does anyone have any ideas what is going on here?