See this TurboTax support FAQ for the Mac minimum system requirement for the desktop software - https://ttlc.intuit.com/questions/1899173-minimum-system-requirements-for-turbotax-mac-software
You can request a refund of the software purchase at this TurboTax website - https://support.turbotax.intuit.com/forms/refund-request.jsp
The TurboTax online editions are on this website - https://turbotax.intuit.com/personal-taxes/online/
