A2Billing on FreePBX Installation (GCP) -- 2

I have a, Asterisk, FreePBX and A2Billing Server installed in Google Cloud on a Free PBX. I need help to configured it so that I can bill departments in my I have already installed A2Billing asterisk server and set up a Sip Trunk to my VoIP provider. My internal free PBX extensions are working, however, I need help in configuring the A2Billing servers. I have already set up the following: 1. Free PBX & Extension 2. Free PBX routing and dial plan 3. Sip trunk to VoIP Provider 4. Outbound dialing rules 5. Rate and & Call plans 6. Customers 7. VoIP Service Provers trunk and connection I do however need assistance with the following: 1. Setting up the System base currency to South African Rand (ZAR) so it updates all other currencies to cost based on the ZAR price through the standard Yahoo Finance Integration already present. 2. Ability to create new Realtime ChanSip, PJSip and IAX accounts that FREE PBX can connect to without needing to re-load A2Billing. (DB Accounts) This should however not affect the Free PBX configuration 3. Configure and setup custom branding on A2Billing with our own logo's and for customer portal/login 4. Configure A2Billing to allow for multiple pre-paid and postpaid Sip and IAX2 customers 5. Install and configure Fail2ban 6. All configuration required from a VoIP service provider using A2billing as its billing engine. The system is installed on CentOS7, running asterisk 14.7 in the Google GCP environment. We will also appreciate any additional advice on how to secure our server from unnecessary registration requests, UDP/TCP traffic and any other security we need to implement to protect our server going forward. A successful candidate will also need to be able to give details on how to give access to the server on the GCP. We prefer a candidate that can configure the server via Teamviewer or log-me-in so that our tech team can monitor what they do and learn from them. They will also be required to sign our corporate NDA.