Hello Greg,
on your spam quarantine when you click into the settings
There should be a little button called:
"Notify Cisco Upon Message Release" with a tick-box.
Tick this option.
When you release the email to the end recipient, a copy will be sent to our automated spam database as well to be reviewed.
Once done and you would like to know the status of the review if it's been corrected by the automated process, or if it requires further intervention due to the issue still being seen, you can open a TAC case with us and let us know of the original sender of the email and/or subject of the email so we can have it checked up for you.
This option is applicable on both the M series and C series.
So you can enable this on the M series device as you're using an off-box quarantine.
I hope this helps.
Matthew