All of the buttons on the phone can be tricky! The mute key is on the top of the device, and has a speaker with a line through it. I have included a link, but you will need to scroll down to the bottom of the page. There will be an image that points out the mute key. These are the instructions for the newest Blackberry Curve. If this is not the device you have, you can go to VerizonWireless.com/support and search there.
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