College changed scholarship after school started

Location: Longmont, CO

I need legal advice on the title. My kid got a 15K scholarship to go to a local university, after evaluating all our options we decided to pick that university in big part because of that scholarship. School started on August 19th and we paid the semester in full on that same day. Now, on August 26th my son received an email stating that due to an administrative mistake the scholarship needs to be adjusted from 15K to 4K. This is obviously unacceptable and they refuse to take any kind of responsibility and their "solutions" involve ways of me getting money through a loan or other scholarships to pay what I now owe, an extra $5,500. What are my legal options here?