Voicemail too long

Hi forum
We’re using FreePBX 6.12.65-26
An unfriendly caller has phoned from a blocked number.
When a number was requested by Privacy manager, s/he unhelpfully entered 0000000000.
When the call was not answered, s/he left voicemail thats over 4900 minutes long.
The recording is a 4GB .wav file !
So, I need to limit these voicemails to around ~15 minutes. Should be plenty.
In FreePBX, I look at Settings, Voicemail Admin, Settings.
What is difference beteen maxmessage and maxsecs ?
The popup is same for each of these options “Max message time length”.
Should I use either, or both ? Its a little difficult to test.
Somewhere I read one of these is deprecated.
But they both listed in current wiki.
TIA’s for any tips or clues