I want to know if there is something like a proxy, but for cellphone calls, not for smartphones, but controlling it from computer??
Why don't you just use an app like Skype and use a VPN or set a proxy?
You can run the call on your WiFi and use Wireshark to trace the info of the call. Or set your computer as the cellphone's access point and use a proxy for your PC. To hide yourself online even more, change your UserAgent ID.
I typed this and saw the "no smartphone" part, so ignore if this offers no help. It won't be possible on a normal cell.