Nexus 5 - Network/Antenna problem

I am using a Nexus 5 purchased from google and running lolipop OS on Wind network in Canada. Had the service running for 6 months without issues and suddenly it is unable to connect to the Wind Network - the only available option in the Network Operators setting is Wind Away which does not let me make any calls or have any internet connectivity. A service rep of Wind put in another SIM and had the same issue after which he said he was an antenna issue on the phone but was not able to tell me if its an software or hardware issue. Thanks, Sam