Did you have your texts backed up somewhere (cloud, app)? If so, they should be recoverable from that cloud service/app; otherwise, once texts are deleted from the phone, they're gone.
I can relate to not wanting to lose an important text message conversation, hpjournal1. It's vital that you know the best way forward and I'm happy to shed some light on this. tikibar1 had a great question regarding whether or not you backed up your content such as text messages to a cloud service, if so, have you tried recovering the text message from your cloud backup? Do you use a third party app or the default texting app such as Verizon Message+? While you can't view the content of text messages, you can view recent text message logs on MyVerizon. When signed in, go to "data", select the line and then "view messages details". Does this help?