Please explain

I would like for Cell C to explain to me how it's possible that apps can still use my number after I suspend it. According to the agent they have no control over the apps , like WhatsApp , which is understandable , but if I suspend my line how can messages go through. I can not make , or receive calls or messages , but messages on WhatsApp still go through. My only explanation is that the agent did not suspend my line correctly , and if that is the case then I'll have to take this matter further as there was serious consequences. I can't understand how this is possible. If my line was correctly suspended no app would have possible to use my line. I would like to hear what their excuse is going to be.