What should I do if TurboTax forced me to snail mail my Fed return, my package shows as delivered by USPS as of 2/12, but as of 4/11 the IRS has no record of my return?

IRS has no record= Not in Where's My Refund

Basically I want to know if I should resend, or perhaps file online using the "IRS Free Fileable" form. I am due a refund if that influences the best course of action.