Black hat seo calls !!

Have been wondering how tech support industry is generating inbound calls for call centers through black hat seo , For example amazon prime calls , bitcoin calls , antivirus calls , router calls etc. And they are really making lot of money out of this around more than 300$ a day which is a big amount .
Simple way of doing this when user searching for amazon prime support number on google, they see tollfree number , which is off-course not of amazon , users are then routed to the desired toll free .

my question is can some one explain how they do it ?
how they rank the desired toll free number to the top of google page in a day ?
I am new to seo , and desperate to learn this process , Any help would be appreciated ! Thanks

Give the support yourself.. rank a site for the keywords.

What more is there?