i need a loop guard protection in mikrotik or spaning tree protocol....

like 4 uplinks of different areas

1= garden
2=office
3=cafeteria
4=wireless mesh wds

so now i need just a security for my internal servers and for my other areas prevent disconnectivity by looping area.
one of my enemy is doing every weak for me this sometimes does this from the wireless and sometimes he put the loop from a switch
and i did nt find him because he is doing that in midnight and he is doing from the home. i can't catch him because i am the provider and he is someone from my customer...i just need a security now my servers cpu's goes to 100% also and my other areas get disturbed totally.please kindly help.. and i know that cisco catlyst series switch can do this...cisco catalyst switch can block the interface which is ruining a loop network to secure the other port networks...but i need this in mikrotik because mikrotik is really very awesome and easy to use operating system or a firewall... please... i also cannot afford the cisco catalyst switch...please help me i have three RB750 SERIES ROUTERBOARDS...
thanks in advance...