iPhone Sip client on Verizon

I’m trying to find an iPhone app for my iPhone 5s that works on Verizon. I tried zopier and I get no audio. Any suggestions would be nice. My main function is to allow follow me to ring my cell if I don’t answer my office phone. I don’t want to use my cell number because then I don’t know if the call is for my cell or an office call. TIA

Bria always worked for me and I have Verizon

I use Zoiper on Verizon (albeit on an Android) and have no problems with it (except for the standard data-plan issues). One-way audio is usually an indication of a Firewall problem, so it’s possible that your base install is what’s messing you up.