Hi,
First, if you can, see if you hear anything if you connect a music source via a 3.5mm stereo cable into the input socket found between the Power In and Power out ports.
If so it proves your speaker works and you may have just lost the Bluetooth pairing to your music source (phone?). Have you tried re-pairing the Bluetooth connection?
If that doesn't work try pressing the Call (phone symbol) and the Vol+ button at the same time. Hopefully this will reset your device. You will have to re-pair any Bluetooth connections. Also try the cable connection again.