I have a new Samsung S5 but had the same problem on my old Droid Razr. Where I work we have no cell service at all, but we have highspeed Wifi. Verizon advertises that the Verizon Messages app allows texting over Wifi. I called technical support several times and each time ends with a referral to the mysterious "Engineering Department" which does not speak with me directly to understand the problem. They tell me incorrect information via customer service that the cellular network will not support the Messages app (even though it is over Wifi that I am asking about) and that it is a 3rd party app. They also never respond to a "trouble ticket" and I have no update on the situation unless I call back and wait on hold forever to speak with a rep that is clueless to the situation. Can anyone here help me?