VoIP Billing System development

We are looking for a front end and backend developer for our SIP Trunk reporting system.

We need a payment and analytic portal for our SIP Trunking services. The portal is based of a front end and a backend (admin) system, so we can manage what the client will see:

Client should have access to download:

- CDR
- Rates
- Invoices

Client should be able to read:

- Account balance
- ACD (s)
- ASR (%)
- Total calls made
- Total responses
- Total Minutes
- Caller Hangup
- Callee Hangup
- Number of channel used
- Number of calls per second
- DID Management

The analytic information should be available per start and end date (flexible range)