I checked in on this topic yesterday and saw that some progress had been made. I did a test message and after 6 hours, my MWI light was still blinking and stutter tone still on. Great! As my interest in voicemail is mainly as a backup in case my answering machine breaks, power goes out or internet goes down, I did one other test. I unplugged my Obi last night, left a message, and plugged it back in this morning. The MWI was working fine.
I had not contacted Vestalink about the problem, so since my MWI is now working, they seem to have corrected it on a system wide basis.
ceg3: Thanks for your efforts, they benefitted all of us.