Who uses what for voice mailings?

Question

SMS

Hello!
In connection with the latest (paid) innovations at the megaphone, we decided to completely abandon SMS and switch to voice notification.
What service would you recommend, according to the requirements:

1) API is required
2) the ability to specify which message to play to the user.
3) preferably without surprises, so that the service runs smoothly.
4) without stupid restrictions, like one call every 5 minutes to one client.

Roughly speaking, we send a notification to customers - the order is accepted. But now we want to record it with a voice.