Stop using your speaker.
Groupon has contacted all owners directly: Check your emails for instructions about how to receive a refund.
If you do not have access to that email or for more information, contact Groupon through their website.
Sold online at Groupon from 24 October 2017 to 3 January 2018
BT505 Bluetooth Speaker - comes in black or white with a red ‘f’ logo on the front.