I'm also stuck with this, but on a real phone number. The company phone number can't receive texts and the audio call cuts off some of the digits (I assume the message is poorly designed and read too fast so it's mostly finished by the time the call is routed to a person to answer it), so both are useless. This process sucks. It'd be good to have some clarification about what business or legal documents can be used here so we can verify by that method instead.

Having the same problem as dgarciadev. By the time the audio verification reaches a human the audio message is mostly over so we only hear a couple of the digits. It's a poorly designed process for corporate telephone systems.