Hey there! I'm sorry to read about your SIM trouble - can you double check that your SIM is inserted as shown here: SIM card: Samsung Galaxy S4? Is this an active SIM that you're moving over from another device, or a brand new SIM card, and is this a phone you've used before? Do you get any error messages about the SIM? Please let us know a little more about what's happening, we'd love to make sure you're able to get this working!
Just checking in to see if you tried the steps above. Please let us know if you need more help.