Unlocked Sprint Galaxy S7 wants me to contact Sprint for international calls on Virgin Mobile Canada

[AC Question]

Hi, I just purchased this phone and it makes domestic calls fine. The phone is originally a Sprint phone and I've used it with a Fido and Virgin Mobile SIM with no issues for domestic calling. However, I can't make international calls. Even though I'm on virgin I get a voice message from Sprint asking me to contact them to activate the feature? Does anyone have an ideas?

Many thanks!