Dear Sir,
I have already did the same project for 2 other clients.
My Project has same features you want and many other features that will satisfy you more.
My Project has ::
1. Account Balance Show (Based on custom Script will be copied on your server to show balance and customer info)
2. High Quality voip Encryption to by pass all kind of Anti Voip Firewalls and tested and guranteed.
3. Topup Account Link , possibility to send userpass to keep the link as simple as possible.
and many more.
Surprisingly , I have it ready and I can send you the samples for other companies i have already finished.
The Project supports : iOS, Android
Also , on your request , BlackBerry and Windows Phone.
Let me know if you are interested.
this will be only for Android.. and for iOS and more... need more .I mean 250Euroes for only Android