Call Centre Just does not Respond

I sent an email to Vodacom Customer Care regarding a query about my contract ***. My email was read followed by a computer generated acknowledgement under ref 001J- JLZP with a promise that they would respond within 24 hours. Well its 3 days later and as usual they just do not respond to email queries. This is not the first time. Emails are just read and ignored. A recurring problem. Maybe they should do away with emails or better still get rid of those who read our emails but don't action. I need Vodacom to do the right thing and respond to customer queries. I expect a response form them in addition to a full investigation as to why they do not respond to emails.