I am not a Funcom employee but:
- anti-undermesh protection was enabled on official servers for Exiled Lands not long ago. It doesn’t destroy already existing structures but prevents players from accessing them by killing them.
- there are certain locations which the system does not detect due to various reasons, some of them are fixed with the patch which is currently being tested on TestLive.
- you can find Funcom’s reporting policy here: Official Servers - Terms of conduct, guidelines and procedures. Please do not expect an immediate answer, it can take weeks before your report is reviewed and eventually any action taken.
- in addition to the above, Funcom has been working on their telemetry to receive information automatically when people are accessing locations which are not supposed to be accessed. It will help them improve their anti-undermesh protection and hopefully, reduce the backlog of reports related to that.
If you ask me as a player, next step is to destroy whatever is located undermesh, however, Funcom have to be very careful how it is implemented in order to avoid false positives.