Write an Android application, Iphone and Windows application

Required a Voip based calling application to work with VoIP SIP/IAX2 platform for international calling. I would prefer if developer can use an existing opensource App and customize as per our requirement, such as Mobisnow or Zoiper an app which can facilitate to check/add balance on the account etc, with standard dialer features standard features, where customer can recharge their account using credit card and Paypal, refill history, rate search etc. more of less same features as mentioned in your website. * *Flexible Feature Set*- Add and remove features to either simplify the softphone or to add extra functionality. * *Branded*– Softphones branded to our name and logo. * *Contacts Integration*– integrated with the address book for simple dialling. * *Auto-provisioning*– Installed and provisioned via a QR code. * *Balance Display*– Display of available balance from A2Billing * *Flexible Design*– Flexible look and feel of the interface. * *Codec Support*– As standard, G711 and optionally g729 * *Protocol*– SIP and IAX2