For computer users
Check that your speakers are on and the volume is turned up. Make sure you hear audio from other websites. Next, try clearing your cache/temporary internet files. Please also check that your internet browser and Adobe Flash are up to date. You might also try using Mango on a different browser.
For app users
The sound level in the app can be adjusted using the volume control buttons on your device. If the problem persists, try uninstalling then reinstalling the app.