I would certainly recommend trying a service that is decent at blocking crap from getting in…
Its effective and costs pennies and worth a shot to see if it helps in any way, developed by one of our posters for his clients … (do a trial)
http://forum.mikrotik.com/t/moab-mother-of-all-blacklists/122053/1
However if you have money to burn you could look at this alternative (if the first one above doesn’t pan out at all)
https://axiomcyber.com/shield/