iPhone: bad antenae or malware

After a few yews of loyal service I gave my daughter my iPhone 5 and got a new phone. She has been using it for moths but suddenly it has gone into "Searching" mode looking for a Verizon signal. Hours with the Verizon techie has produced no results and they are concluding that it is a bad antennae. Now my daughter comes back from school and found out that others in her class have had their phones disabled as well. Has anyone heard of something like this. Could it be some type of Malware? I'm used to Microsoft Virus's but don't know where to go with an iphone.