@Samvvand
What is the led status of the TD-W9970 now?
Try to log into the web UI of TD-W9970 and verify whether it has obtained valid internet IP address and gateway. If so, please change the DNS server to 8.8.8.8 to give it a shot.
And you can contact ISP to verify whether there is any special settings need to be done, like IPTV.
Besides, you can reset the TD-W9970 and connect your computer to the LAN port and setup the broadband connection on the PC itself to verify whether you can access internet.
https://www.tp-link.com/support/faq/921/
Good day.