[happylion0801]

There is no such thing as unlisting a number, atleast last time we tried multiple times but it still keeps showing up

[jabl]

IIRC when looking into this some time ago, if someone who has your number uses truecaller then your number will reappear. So depending on your level of paranoia you might want to regularly check that unlisting page.

[rootsu]

I have tried this for both of my numbers and it has worked quite well. May be you need to try it one more time?