[jggimi]

I also have an ISP (25Mbs VDSL) that provides a custom configured 2Wire brand "Residential Gateway" which combines IPTV, VOIP, and internet access. But unlike yours, the connection is not pppoe; it is standard Ethernet:

{ISP's private IP network} - [RG box] - {local analog phone}
                              |    |
                              |    |
                              /    \
                             /      \
                            /        \
                     {IPTV net}  {Internet}  - [OpenBSD router] - {IP net}
                172.16.0/24             75.x.x.x         192.168.1/22

Obviously, I don't know how your network is configured, and I don't use pppoe, and may or may not be able to help with a pppoe-specific configuration issue.

Post your network topology, such as I have done here. Post your configuration files: hostname.<nic> and your ppp.conf file.