Decent reviews on amazon. Just remember, you get what you pay for. The bitterness of poor quality remains long after the sweetness of a low price is forgotten.
As stated above, the settings are in the display. They may have had to disconnect the battery which may have reset everything back to factory default. Check your owners manual.
Not sure what you mean by "when drive onto a bumper", but if you are saying you hear a clunk when you drive over a bump it seems it would be more suspension related than brake related.