How to retrieve lost text messages? Sprint iphone 5?

My iphone 5 wasn't working properly so I went to the apple store to get it fixed. They replaced it with the new phone. However, I was waiting for a text from someone when they did it. The phone was not activated right away because they said the Sprint server was down. I waited a couple hours and retry but didn't work. I took it to the Sprint store and still didn't work. Anyway they finally solve the issue and got my phone activated and restored all the contents next day. However the time that my phone was off service, I may have received some text messages. I know this because I told my friend to text me during that time that my phone service was off. So the message was definitely send to me. When I finally got my phone restored back to normal, I couldn't find any new messages and even the message that my friend send wasn't there. How can I retrieve all the messages that were send to me during that period.

No messages were sent to you during this time. They are stored at Sprint servers and sent then. When your phone was deactivated the messages are stored until your phone is reactivated. They stay in circulation for 60 days. The message might not have gone thru, but you should get the messages sent to you by your friend. They shouldn't be "lost"

No way, Sprint can't help you retrieve any of them. But I have recovered deleted text messages from my iPhone 4s by using an iPhone data recovery software.

Here is the tutorial that helped me:
http://www.iphone-data-recovery.net/iphone-sms-recovery.html

Hope I help!