paying for no service

This would be my second report within 2 weeks. My first report was quickly resolved. Unfortunately the product I have received on 16/05 does not work. I have phoned vodacom everyday since then. And I am only told they are working on the problem. How much longer must I struggle with vodacom. Including my first issue it has taken vodacom 2 weeks not to solve my problem. I am paying for a product that doesnt work.