When you have an app to spy WhatsApp messages like mSpy, you’ll also be able to check their call history. Remember, people use WhatsApp not just for texting from one phone to another, but also for voice conversations. There are lots of reasons for that. First, there are no long-distance charges, which is handy if you’re calling long-distance. And second, there’s no trace of incoming and outgoing numbers on their phone bill. Remember, if you call someone from your regular phone app, the number shows up on the user’s phone bill. Those who want to be more discreet may choose to opt for WhatsApp for phone calls. But now there’s a way to bypass that discretion and see who they called.