SSI (supplemental security income) is not taxable or even reportable. SSDI (social security disability income) only becomes taxable when added to sufficient other income.
Either way, it sounds like you have no taxa liability to offset with an education credit or dependent credit. One of the credits, The American Opportunity Credit (AOC) is partially refundable (up to $1000). It's 40% of the 1st $2000 of tuition and 10% of the 2nd $2000.
The student must be your dependent and a half time or more student at an eligible school. Grad students are not eligible.
If you are eligible, you have answered something wrong, in the interview. But, a lot of people are just not eligible. See Also see this TT support article https://turbotax.intuit.com/tax-tips/college-and-education/what-are-education-tax-credits/L7TuLrVqZ
https://www.irs.gov/Individuals/AOTC
https://www.irs.gov/newsroom/american-opportunity-tax-credit-questions-and-answers
https://www.irs.gov/credits-deductions/individuals/education-credits-questions-and-answers