Has it ever worked? If so, what changed just BEFORE this behavior started? A new app? An update? Something else? Think carefully as the smallest thing could be causal...and attempt to undo whatever that was.
If this has never worked, then you should seek formal warranty support (if you indeed remain in your warranty period) from your original place of purchase or authorized service center (depending on region, it can be different...you should have received documentation concerning your specific warranty provisions when you originally purchased your BB).
Occam's Razor nearly always applies when troubleshooting technology issues!
If anyone has been helpful to you, please show your appreciation by clicking the button inside of their post. Please click here and read, along with the threads to which it links, for helpful information to guide you as you proceed. I always recommend that you treat your BlackBerry like any other computing device, including using a regular backup schedule...click here for an article with instructions.