I'm working for Engineers Without Borders Galicia and we are migrating our volunteer managing system to CiviCRM. 
I'm experiencing something quite like this bug:
https://issues.civicrm.org/jira/browse/CRM-15702

I can send SMS to individuals from his profile page, but bulk SMS are not sent , although the report says the job is completed. The users in the group (a one man group) have all emails. Our SMS provider is Twilio and there is no trace of the bulk sms. The normal ones get perfectly sent (and logged).

Any help would be very much appreciated.
Iván Lago.
IT Engineer at Engineers Without Borders Galicia

More info: 
Server version: Apache/2.2.22 (Debian)
CMS:            Drupal 7.36
CiviCRM version:5.6.0
PHP:        	5.4.39-0+deb7u2
MySQL:          5.5.41-0+wheezy1
SMS Provider:   Twilio (test acount)