I used to use Twilio in an old business of mine. I ended up stopping when all of the regulations started to come out a few years ago. I kept my Twilio account though... why? I really know how to abuse their services. Chances are... the people that are calling you are using Twilio or something like it.

The key thing to remember is that these scammers are often NOT in the US despite having a US phone number, and this means a big difference in cost per call or text message between the two of you (assuming you are an American).

What I am trying to say is that I kept my Twilio account. When I get a strange call or text I will 'probe' the number a little... see if it accepts incoming text messages or incoming calls (you can see in your Twilio logs).

Lets say the number accepts incoming texts or calls. In this case I will blast the shit out of their number with multiple Twilio numbers, and sending 1000 texts costs an American about $7. If the number in question belongs to a foreigner (lets say India), sending them 1000 texts be the equivalent of a day or two's pay (or more).

I've done this on several occasions and often times they will shut off the number to prevent incurring further charges (it costs money to receive incoming calls/texts with Twilio and other services).

So a text message might cost me a fraction of a cent, but it costs them even more depending on their currency.

I've even made some recordings of robocalling them back... one number answered the phone with IRS, then FBI etc etc. These people are crooks for sure, but you can have a lot of fun fucking with them. And it's going to cost them a lot more money.