I've been struggling to do a sim swap for 2 weeks now and it looks like it will take forever cause I'm afraid that my number will be given to another person whilst I've had the number for yesterday now

I've been struggling to do a sim swap for 2 weeks now and it looks like it will take forever cause I'm afraid that my number will be given to another person whilst I've had the number for yesterday now. I've had my number from 2010 then later in the years I got a call from Mr price offering me a data contract as I've had an existing account with them. I lost my phone on the 6th of March and I've been trying to do a sim swap from the 8th, since then I was dealing with Mr Price to release my number from contract to prepaid and that was but done till date, I'm unable to get my number back as on MTN's system my number shows as inactive. I've been calling MTN for a number of times to no success as I keep speaking to different agents everytime and they don't seem to know what they doing, my fear is that my number will be given to someone.