No longer a rogers customer, using apps through wifi
I have an iphone 4s through Rogers however due to traveling overseas for an extended period I have just canceled my account. I don't want to get another provider as I'm not staying in any one spot very long. Because I'm still using this device over wifi I'm wondering if anything changes with how I use whatsapp/viber/facetime. As I understand it these apps connect my contacts with my phone number. Now that I've given this number up how can other people add me or contact me through these apps? Is the only way for me to add their number to my contacts then send a message? If someone else takes over my old number will that mess things up and have my friends messaging the wrong person?