Welcome to the Community!
We'd like to take a look at your account in order for us to check as to why you're struggling to receive incoming calls. Though we're able to pull up a record using your community details, we're uncertain if we have the right account.
Can you send us a PM with your customer ID or username together with your service address?
For your reference: How do I private message (PM) in the community
Thanks for providing your account details via PM.
We checked your account and we found that you're actually on the NBN FTTP technology. We just want to clarify when you mentioned that you connected the phone to a modem, were you referring to the NTD box on the wall wherein you connected the handset to the UniV1 port?
In addition, were you able to perform a test on your own by calling your homephone number using your mobile?
Thank you for the clarification, @sunkyounghwang.
We've escalated the case to our Engineering team for further investigation and they'll be in touch with you via SMS or phone call within 24 to 48 hours.
In the meantime, if you have any further enquiries or require general information on the matter, contact us here and we'll be sure to get this coordinated for you.