Poor Service

I bought a R209-Z modem prepaid for R800 to come home and find that it doesn't connect to even my phone yet at the very same time on the Vodafone mobile wifi application it's appearing as connected and the bundles are being used. It can't be that someone else is using it cause I opened a few minutes ago I have the wifi key with me. R800 is not something you can easily throw away. I want to know what I can do from here onwards because I'm very disappointed and unhappy with the product and the service as well. Please help me