My iphone 5c doesn't receive misses calls or voicemails when off?

When my phone dies and then I turn it on I only get text messages but it never shows I got any missed calls or voicemails when I know people have called? I'm waiting for a important call is there anyway to receive my missed calls and voicemails? Its kind of a big deal and I lost my charger so its been dead until now and I want to retrieve my calls. I don't have it on do not disturb or any of that.

No phone will show a missed call that you got when the phone did not have a signal, and if it is off you will not have a signal. The missed calls are stored on the phone itself, the voicemails are stored elsewhere and you should be notified if you have one when your phone is turned back on (but you can also call your voicemail to make sure, as it is possible that you would not be notified if you are using visual voicemail).