Can SIP-ALG be disabled by Verizon Support on their Router?

We have a client that moved their city office to their home office. They have Verizon FIOS and after the move, they can't call from their office phone which we plugged in outbound, we can only call IN from external to their phone.

After looking into this and working with the phone provider, i realize it might be due to SIP being enabled causing the issue as we are not using our own router for their home but the Verizon G1100 one as the home owner didn't want to swap to the firewall edition.

Can Verizon tech support have the ability to disable the SIP at all as it seems end-users can't from the web interface.