You may need to re-pair your headset with its wireless receiver or pair it with a replacement receiver. Here's how:
Initiate the pairing mode for your headset
Download the pairing utility from the UE 3500 Support page and run it.
With the headset powered off, hold down the Multifunction button for nine seconds (the indicator LED will blink green rapidly once in pairing mode).
NOTE: If your headset is powered on, you'll need to turn it off first. Press and hold down the Multifunction button for six seconds (the indicator LED will flash red when powering off).
Initiate the pairing mode for your wireless receiver
Make sure your wireless receiver is connected to a USB port on your computer.
With the headset in pairing mode, click Next on the Pairing Utility page to initiate the pairing mode on the receiver.
Once the headset is paired with the wireless receiver, the connect LED will turn solid green and the pairing utility will state that the headset is ready to use.