modem: AC1200 Wireless VDSL/ADSL Modem Router / archer-vr300 

Firmware Version: 

1.6.0 0.8.0 v009c.0 Build 241022 Rel.36126n

Hardware Version: Archer VR300 v1 00000000

this is from my modem page but the real hardware version is: 1.20

I have the latest update, and I'm having a weird issue with blocking devices on the modem, which hasn't been resolved in any update yet. When I block a device, it actually blocks internet access. However, if that device making a voice/video call over the internet, it doesn't block it. I have to reboot the modem to completely disconnect the internet, which in turn forcibly disconnects all devices, unfortunately. This is a very weird issue, and I've been experiencing it since I bought this modem two years ago or more. What i want is, normal block, when i block the device access it should block all access (including voice/video call over the internet blocking) without reboot the modem.