Twilio phone service retry outbound calling just once

Question

Using the Twilio phone service, we make outbound calls:

curl -X POST 'https://api.twilio.com/2010-04-01/Accounts/ACc1....4658a/Calls.json' \
-d 'From=%2B44987654321' \
-d 'To=%2B123456789' \
-d 'Url=http%3A%2F%2Fourdomain.com%2Ftwiml.php%3Faction%3Dcall_is_taken' \
-u ACc1....4658a:{AuthToken}

Not that it matters, but when someone picks up the phone, our response twiml code (which will change) is just:

<Response><Say>Thank you for picking up.</Say></Response>

The problem is when someone is in a meeting: The phone rings, the user declines the call quickly. Stupidly, Twilio retries immediately, and if the user declines again, twilio will try up to 7 (!) times immediately.

Realistically, the user will run out of the meeting, pick up the call and hear that it is not a life-important message. Imagine the fury.

How do I tell Twilio to only try to call ONCE?

Answer 1

This problem happens when using Dial verb as well and it is very annoying that Twilio documentation doesn't mention this continuous retrying. There has to be a way to prevent retries as like you say it is a show stopper for a lot of situations.

Here is a link to pretty much same issue on Twilio forums: http://forum.twilio.com/twilio/topics/outbound_calls_keep_incessantly_retrying