@des.owers So sorry that the Robovac 11 doesn't work normally when it knocks into a wall or chair. Be assured that we are more than happy to arrange an exchange if the issue turns out to be with our product.
Before that, could you please confirm more details about the beeps and the flashing/solid red indicator the machine gives out. Also, whether the machine would knock into while walls or furniture? Please also try to tap the bumper a bit more vigorously a few times and see if it helps.
If you don't mind, please contact us at email@example.com with the topic, so we can arrange an exchange if the issue cannot be resolved. A video that can show the problem would be highly appreciated.
Appreciate your time and effort!