If I restore to Windows 8.1 will I have to buy 10 again?

[Windows Central Question]

So my college decided not to support Windows 10 for the upcoming semester. I bought a new laptop before this and got the free upgrade to Windows 10, I got an email weeks after Windows 10 was already out saying that if I had windows 10, I wouldn't be able to download anything from the system our college uses. If I restore back to Windows 8.1, will I have to pay $150 to get Windows 10 back? which is way better than 8.1 to begin with.