My Isp Is Threatening To Take Me To Court For "stealing Internet"

Location: North Carolina

Good day,

*TLDR at bottom*

I live in a rural area on a 5 acre lot with 2 homes. My parents own the lot and the main home and I rent the accessory dwelling (2 different addresses) from them. The first year of renting, I tried numerous times to get internet service from the ISP that feeds the street (THERE IS ONLY 1 ISP!). They told me they could not add internet in, as there were not enough ports to add an additional for another home.

I inquired with other ISPs, only receieved denials. My only other option was sattelite interent.. which I was not up for given the prices lately. For internet for the first 6 months, I initially added another line to my phone plan and used a hot spot.. which after a while I found was not sustainable.

Myself and my parents did some research on ethernet cables and found out that extra long ethernet cables can work for up to 320 feet... my home is only 230 feet away from their home. We did some research on the code for internet cables. We ended up running a cable from their house to my house. We bought direct burial cable and conduit. Ran said cable. Hooked it up and installed surge protectors. Now, I have 350mbps of reliable fast internet. I split the internet bill with my parents.

Ive had this set up for the past 2 years. In the past months, the ISP's trucks have been driving in the area. One time, one of their guys stopped and questioned me about how I had internet. He was kind of pushy. Asking where the internet comes into the house and how long have I had it. I explained I pay the landlord for internet, youd have to ask them. The ISP has asked my parents numerous times if they could "inspect" their equipment as a "courtesy" but they've told them no numerous times, citing their internet works just fine.

A month goes by, I get a letter in the mail asking me to cease and desist use of the internet. Saying that im not paying for internet access. And that they would be taking me to civil court if I did not get off of the internet. My parents get a letter threatening to sue them if they are knowingly providing me internet.

I am not tech savvy. All I know is internet comes from the box at the street > modem > router > devices via wifi / ethernet.

My legal question:

How would the ISP be able to take me to court when I asked them numerous times to provide me internet? (I have this documented with emails and phone calls). The ISP's engineering department denied hooking my house up to the internet, saying its "1 port per 1 property, not per house" which I have a recorded call of this conversation. Even after I appealed their denial, they marked my ticket number as permanently closed with no option to appeal.

Am I actually "stealing" the internet? Im paying 1/2 of my parents bill. Which would be the same usage amount if I lived literally under their roof.

How did the ISP find out I was on the wifi?

I appreciate any advice on this. Im continuing my life as usual for now.

EDIT: my parents nor myself have told the ISP about the cable thats buried I dont pay a separate bill for the internet, the price is included in my rent. The ISP somehow knows the wifi is coming from their home.

TLDR: ISP denied hooking my house up to internet, myself and parents ran a internet cable from their house to my house, ISP found out and now threatening to sue.