Where do cloud PBX providers purchase virtual number capacities?

Question

Telephony

Hello!
I'm looking to purchase ~500 virtual numbers with call recording and call forwarding. At the moment, I settled on the provider zadarma.com (120 rubles / month for a virtual number in the code +7499). Before that, I tried comagic.ru. I also see that there is a sipout.net service, where prices start from 99 rubles / month for +7499.
Question: where do these providers purchase number pools themselves? Is it possible to purchase only virtual numbers with the possibility of forwarding, and implement all the equipment (which is provided by "cloud PBX") in the form of recording conversations and routing calls in your own PBX on your side?
I am looking for a cheaper option, since part of the functionality provided by the companies listed above (callback / call-tracking / sitephone) is not required by our organization.

Answer 1

For a friend who wants 500 numbers, you somehow use Google poorly. Get a license and become a provider yourself.