Cable from street cable box to house replaced and new one doesn't support 2 GBps plan speeds

Recently, the cable conduit from the street cable box to my house was replaced. I immediately noticed that the new cable is significantly thinner than the previous one. The original cable was installed to support Gigabit speeds and had been performing well — I was regularly achieving speeds of 800–900 Mbps (via objective third-party tools such as Speedtest.net), even though I was subscribed to a 2 Gbps plan.

Since the new cable was installed, my connection speed has dropped drastically. Even with a computer directly connected to the modem’s Ethernet port, I am now barely reaching 300 Mbps. No changes were made to my setup, aside from the cable replacement, and I am confident the new, thinner cable is not capable of supporting the speeds I am subscribed to.

I request that you:

Investigate this issue immediately.

Send a technician to replace the current cable with one that properly supports 2 Gbps service.

Please do not ask me to perform extensive troubleshooting steps, as the cause of the issue is clear and directly linked to the recent cable replacement.

Additionally, while your internal speed test tools report expected speeds, third-party tests (such as Speedtest.net) do not. I expect results based on industry-standard, independent speed tests, not internal tools.

I appreciate your prompt attention to this matter