In Simple CRM, you can prevent users from exporting data as CSV files (Excel / OpenOffice / LibreOffice).
connect to Simple CRM with an Administrator account
go to the module Admin CRM (menu top -> Admin CRM)
click on the "User list" tab
click on the user concerned
uncheck the box "Can export data".
click on Save
Once this box is unchecked, the user concerned will no longer see any button "Export to CSV".