No incoming calls, goes to voicemail

[Kataris]

I am able to make outgoing calls on my Freephoneline Desktop application, but I cannot receive any calls (they instantly go to voicemail). My connection seems to be fine, and I do not have any firewalls enabled. Upload surpasses 2 mbps as well as download in terms of speed. I've restarted the software to no avail. My ringing mode is set to Simultaneous as well.

Freephoneline passes all connection tests and worked previously (but not lately).

I tried entering a support ticket but got an automated response that closed my ticket, stating that they do not provide support for Freephoneline Desktop. My landlord owns the router I'm using and is unwilling to bridge it. Will I have to live without any reachable phone number? (There's no cell phone reception in the basement apartment I live in, either, nor are there phone jacks)

[sinister.groupon]

If you are not in charge of the internet, and clearly there are multiple PCs in the house, how can you confirm that you have no "firewalls" enabled?