Dear all, its good news for me we reached 1000+ customers for our company running as ISP. I am looking for a setup with premium quality service provider.
Bad news is, I am still worrying that our backend is still not capable enough to adopt this change every month.

I need all your suggestion as I am briefing my setup so far and what I am want in future. I think it is good for everyone those are reading this post:

Servers(AAA & billing & Helpdesk)- Achieved: I am still using paid solution which is combined of all three, with integrated epg and SMS gateway. All feature are there.No hassle
Future: I am still looking to save money, so looking for one time cost unlimited users license.any alternative is welcome
Ivr setup: Achieved : It is working fine, complaints are easy to handle now. little bit cost is there.
Future: want a helpdesk system with ivr integrated to it with SMS notification, still looking to it but no success.any helpdesk suggestion?
Monitoring(Nagios with centreon ) :Achieved : It IS working as basics level.
Future: want a simple setup for monitoring with SMS notification for down scenario, any alternative is welcome.
Uplink routers for 2 WAN: Achieved :still using Mikrotik CCR individually for both WAN, Policy routing has been done for failover(server side).only brige network setup on CCR
Future: I think I am wasting resources it can be done on same CCR.
Sever side access network (Cisco Switch):Achieved : using a cisco switch with vlan interface to access internet for all customer.
Future: I think at this side a mikrotik router can do more, whats your suggestion! each customer what they are doing in my local network, all can be monitor.
Network Deployment (outside Network): Achieved: All FTTH network has been deployed with outer electric cable from office. Fully satisfied with efficiency.
Future: dont want to use electric power to run CPE from office. is any alternative, cheap one?
Power backup::Achieved: Two UPS with 6 hour backup, one for NOC and other for outer CPE.
Future:Stll cant able monitor those UPS as they are cheap, is any UPS can be monitored with Nagios? suggest please.

All thing is done in within 1 year by myself alone. But I feel some is missing. Each month customer complaints are growing as network is slugging now.
-I hear Cisco ISG level technology which is enterprise level technology, what if i used it now rather then PPPOE servers and billing.
-No firewall is deployed yet , which is suited to our network please suggest. as we are facing some Spam mail threats from users.
- thinking to deployed a Cache server and torrent peering, any suggestion on this.
- Main thing customer are growing but issue are also growing, what need to be done from side to pppoe disconnection will resolve, maybe PPPOE is not reliable ! Users get the pppoe ip with username & pass but browsing is not working, I can't find anything why it is happening

I want to depolyed a backned an enterprise level with more reliablity, so that customers can use internet without any disconection.
All suggestion are welcome! I am here learn and give some: sorry about my english

My advise, in order not to die from success: go hire a consultant.

Your questions don't have simple answers, and to properly answer them, much more details about not only technical aspects of your business, but to the business itself are needed.

https://mikrotik.com/consultants