this following assumes you e-filed and got an acceptance e-mail.
you need to follow up with the IRS as to what the fund status shows.
https://www.irs.gov/refunds
if it shows it was sent then you need to follow up with the IRS for the missing refund
https://www.irs.gov/faqs/irs-procedures/refund-inquiries/refund-inquiries-0
