Obligatory apologies for formatting, I'm on my phone on my lunch break.

OK, so back in 2021, I took my a web design class because I needed an elective. It was an HTML and CSS class. As part of the class, we had to create a website through a site called WebHostingForStudents to practice our HTML and CSS. As part of this, we had to give a phone number for some reason. The professor warned us we might get calls about our website. I shut down the site after finishing the class. Fast forward to now. I've graduated, am working full-time, and am still getting calls about that stupid karking website I made for a class I found incredibly stressful and didn't even pass anyway. The last time I got called about it, I (admittedly somewhat rudely, but I was at work and tired of these people in particular calling me, which I know is not an excuse) told them I wasn't interested and to please stop calling me. However, I know from past experience that this will only buy me a few months tops. How do I remove my number from the registry entry? Thanks