Techs & Trends

I have the blackberry 7100i and downloaded a new theme to put onto my phone. It went through the whole process and now I can't find it in my phone to put it on there. I talked with a lady from bb support from nextel and she said that the only themes that would work are the 3 that are on the phone already. I find that hard to believe. Could somebody please help me and tell me where to go in my phone so I can get this?

Thanks