Iphone5 receives sms messages from a global server (international) in Chinese

We have a VPN structure where a person receives a text code (6 digits) for access to the VPN on their phone using SMS. All of a sudden one of the users began to receive this code in Chinese. It was working prior to that without problem. The SMS was sent to him through his Verizon's network in Native Mode from our VPN server which sends those SMS messages out.  He is using an Iphone 5.  No other user on AT&T network is having this problem. Unfortunately he is only user in using Verizon cause geographically it works better there.