Send large volumes of calls at once with follow-up sequences.
phone_number - (STRING) The phone number to send a call to.sequence.retries - (INTEGER) Number of times to retry when no answer.sequence.wait_period - (INTEGER) Number of days to wait in between follow ups (retries).sequence.wait_period_time_unit - (STRING) Time unit for the wait period. (MINUTE, HOUR, DAY)