[DanBC]

10s of thousands of calls isn't necessarily illegal, nor unwanted.

Phone companies will probably claim to be just a pipe for data, and that they cannot interfere with that data, and that regulation is for other people. They'll stop you if you're damaging their network.

Cynically I'd say that a company making tens of thousands of calls is worth more to the telco than me, making very few calls. (I doubt that's actually the reason.)