FNB duplicate SIM. Nobody cares.

I raised my concerns regarding my FNB Connect contract number being used by a third party with many people getting through to this person asking me why he answers my phone.i was promised a call back which they claim to have made yet I have no missed calls on my phone. So I guess nobody caresbthatbfornsome reason, someone has access to my WhatsApp as well as my number, which is linked to my FNB banking app. I wish someone cared enough. I am now thinking of ways to ensure that Someone starts to care..