How to get refund

I am a college student and I was using EC2 instance for our course homework ( https://eecs481.org/hw1.html ). Instructor told us to use it and it is free but I got charged over $200 even though I haven't used anything.

Here is the post from the instructor : "Here is some simple reasoning. Assuming from Jan 10 to Jan 31 (22 days), everyday one EC2 instance was running for 3 hours on average; this translates to 66 hours in total for HW1. With $0.5 rate per hour (which is not the cheapest), that’s $33. But, I saw many students were charged more than this. So there seems to be something else going on. I’m hoping you could dig deeper into your expenses, try to share as much detail as possible, and ideally identify some root causes of the expenses. That’s going to be immensely helpful for me to make a reasonable request and hence lead to a higher chance of getting refunded. Again, I’m truly sorry to hear that you were charged. Please let me know if anything I can help with."

Is there any possible way to get refund that I got charged on Jan and Feb for using nothing instead of having set up for my HW for my college course?