Cell phone jammers are machines that create a certain level of interference with your cell phone's signal. This interference makes it so that you can't make or receive calls, and you essentially don't have a signal. However, for those who are frustrated by a cell phone jammer, there are ways that you can completely bypass the jammer. You may need to try a few different methods to see what works for you.
Try making phone calls via the Internet. If you have a phone that's capable of making calls over a Wi-Fi connection, then you may be able to use Internet connections to place your cell phone calls rather than traditional voice networks.
Use alternative communication programs. If you can download and use Skype on your mobile phone, then you could make calls using that program rather than the more traditional signal that is being jammed.
Walk away. If you have no alternate bands you can access, and if your cell phone cannot make calls via the Internet then you simply need to get out of range of the cell phone jammer. Once you're out of range, you can place calls normally.