No service with Koodo V3 MicroSIM

Can the version of SIM card possibly matter when using a TELUS iPhone 4? I had a customer that brought in an iPhone, and it would work with our active demo SIM, which was V2 SIM. And the customers active SIM (V3) would work fine in our demo phone. Only combination that won't work is the customer's SIM in the customer's phone.... Totally stumped here...