Can I use turbotax to efile my tax refund because I am a graduate student as a non residental alien. I efile my tax refund early February, but did not receive funds back.

You flat out can not use any flavor or any version of TurboTax to file a non-resident return. Check out https://www.sprintax.com/ instead.

As a nonresident alien, you will have to file a Form 1040NR and cannot use TurboTax you will have to use the partner Sprintax site.

If you have already filed form 1040 for residents then you will have to amend your return, please see these instructions from TurboTaxLina how to amend your return: 

https://ttlc.intuit.com/replies/6023806