Lost iPhone 5s, Is sprint aware if your iPhone is in Lost Mode?

I lost my iPhone 5s today. I enabled the lost mode in the phone and I'm currently tracking it. Does sprint know when a iPhone is in lost mode? Does it know if you lost your iPhone and your tracking it?

If the iPhone is in lost mode, I don't think they know about it, I think that you have to report it to them for warranty purposes. I'm not a sprint customer, but that is how my carrier is. I have Verizon

No Sprint will not know this. Sprint would not be able to do anything about this because some people will put the phone in lost mode to see what happens or as a joke. You will need to contact Sprint if you are not able to find the phone and have them take the phone off your bill. I would suggest not doing that till after though because if Sprint takes away the coverage from your phone, it will be harder to track as it will have to be connected to Wi-Fi.

Definitely call and report it lost.

I'm afraid not. You may learn more here: http://www.wikihow.com/Find-a-Lost-iPhone
If it does not work, it is better for you to contact your service provider and phone provider and see if they can help. To prevent your new idevice from being stolen or lost in the future, I suggest you apply some free anti-theft apps like iLostFinder ( http://ikeymonitor.com/free-apps ) except set up Find My iPhone/iPad/iPod in iCloud on the device. It will take pics of the thief or finder when she/he tries to open your device with a wrong pass and then send the pics to your email etc. Hope it helps.