Logging incoming calls on iPhone.

Logging incoming calls on iPhone.

Hi Community 
Has anyone been able to solve the problem of iphone not being able to pickup incoming calls (or SMS) in the Zoho CRM app? I know it can be done if you have a PBX system, but I just have myself and an iphone. Surely there must be a way to do this. I don't believe it's because "Apple has locked it down" as Zoho states, otherwise the PBX systems wouldn't work either. 

Who is the guru who can solve this?