MTN took to credit bureau because of their own negligence

My man took a phone with MTN 2021 and he got ****** and lost that phone including the number and so after that happened he didn't report at MTN because he felt like it had nothing to do with them as long as there'll be deducting their money cos he never changed anything expect for a ****** phone that he never made any swimswap to get his number back,Mtn stopped deducting and he couldn't see that because he had no phone now all we are concerned about it is why did mtn stop deducting their money and now this is on top of his head? I believe it is their negligence not his cos he never changed banks expect the ****** phone.