https://techcrunch.com/2019/04/11/stratics-data-leak/

If you’ve ever had a voicemail appear out of nowhere, there’s a good chance Stratics Networks was involved.

The Toronto-based company is the self-proclaimed inventor of “ringless voicemails,” providing its customers a way of auto-dialing a list of phone numbers and dropping voicemails without leaving a missed call. The system uses a backdoor voicemail number typically reserved by the carrier to leave a voicemail directly in a person’s mailbox. The company once claimed it can process up to 10,000 ringless voicemails per minute — if you pay for it.