The problem with that is that you have lost part of your rights and opportunities as a phone number owner. What if your long lost aunt Bess passes away and you're in the will to inherit those oil and mineral rights in Oklahoma that they're drilling all those new wells on? All they have is a phone number on you. You're just $hit outa luck, that's what and you won't even know what you missed until years later on your death bed when cousin Jug thanks you for your incredible generosity but asks why you let all of your oil rights pass on to him and his whole buck-toothed family of now fat, rich and happy misfits?
I'm sure the idiots have a contract with the phone company. Either way, if they can afford this many numbers, they can afford to research and locate the correct person they're trying to contact.
They don't have numerous numbers - they use a VOIP system with per-programmed ID numbers to make it look like it comes from all over the country. These slugs are 3 degrees lower than ambulance chasers. If you have a debt that can't be collected, these scum bags try to convince you that you still owe it. Dirt bags with dial tone.