Help configuring Server Cloud

Hi all!
I have a Mikrotik Server Cloud CCR1016-12G, I am using it to with three internet connections to serve my customers better and provide high internet speed connection, here is a sample

every ether net ports is connected to a wireless access point
and here is the configuration for the interfaces
new.txt (5.23 KB)
I am using Usermanager to control the accounts.
but the problem is that every time there is more than 20 customers connected to the network the server goes crazy and sometimes I am forced to reboot the server to make it work again
I used a several techniques binding the ports like what the called the ppc and nth

is there a deterrent method should I use to this kind of networks to make it perform properly? please help

notes: 1-I am using a cheap routers between the ISP and the Server Cloud.
2- the ISP is a satellite connection.
3- and I don’t have a static IP
this is also another image may describe more
D1.png
thanks for your time.

also followed this procedure in this website and the problem stay the same
http://www.wifitech.com.pk/mikrotik-2-wan-1-evo3g-load-balancing-pcc-method/