Fly enough IFR and it’s inevitable that ATC eventually will lose a flight plan. Maybe it timed out—you got delayed and you’re calling for a clearance much later than your scheduled departure. Maybe it simply got lost, was filed under a different callsign or some other error crept into the mix. It doesn’t matter, since without a clearance, you’re not departing IFR.
Depending on the controller and his/her workload, plus how professional you sound on the radio, ATC may offer to fix the problem immediately. A controller can prompt you for enough information to enter your plan into the system directly, without you needing to chase down someone else on the phone or another frequency to re-file. If you can do it with your cell-connected tablet and an EFB app, try it. Otherwise, you’ll have to figure out a way to contact Flight Service and file all over again. Of course, you can depart VFR instead of IFR. If the weather is good, that’s an option, and you can raise Flight Service on the radio once you’re airborne and file, then call ATC for the clearance. But when the weather is IMC or even if it’s just marginal, that’s usually not a good idea.
