Phone saying insert sim card have inserted sim

Try power cycling for the phone. Please follow the steps below:

1. Remove the battery from the phone while it's turned ON.
2. Remove the SIM card.
3. Leave the battery and the SIM card out for five (5) minutes.
4. Put the battery and the SIM back and turn the phone ON.

If same problem occurs, try using another SIM to isolate the problem. If same thing happen after trying another SIM, then the phone needs repair. You may need to contact the manufacturer.

Have a great day!