Hi,
The VOIP based android apps is ready which is our product and having the function which you mentioned.
Our product is ready and integrated with ASTPP and A2Billing. Share more detail about the funtionalities which help us to know the exact time to finish the task.
We need to check by using SIP, Pjsip, Mjsip, doubano is feasible or not.
I think you missed to add one 0 in your budget. Beacuse your current budget in not even audible to change one fuction in existing application and specially in VOIP based Apps.
Discuss with us if your budget is INR 100000 for Android only and if IOS also there then min INR 180000.
Thanks for your time