Bad service ever

I have been using MTN number for more than a decade now and it’s a contract number. I lost my phone 3weeks back and been trying for a sim swap since then. I’m being told that I can’t do sim swap because my number is under a staff number. Been calling head office timeously without being assisted until my airtime gets finished. I don’t know what to anymore because I really need my number back . I have been to more than 3 MTN stores around they say I should call customer care and they also refer me back to them . It’s really frustrating