There are so many companies out there that simply accept any contact number spoken or written on paper.
Why is this a problem you ask.
When it comes to number theft the fraudster needs to know a number that you called so they go to these internet sites or even stores and subscribe your number...
I'm no expert but have been looking at this for some time now. Owning one of these special number with lots of repeating digits at the the end is no fun.
For a SIM swap which is how they get hold of these and other numbers they need some information to answer a couple of the challenge questions...