New parking sensors faulty?

Hi all

Recently had the misfortune of a dozy driver going into the back of my pride & joy, pushing 2 sensors into the bumper, being repaired through insurance as I write this. The repair centre have fitted 4 new OE sensors & brackets but have been unable to get them working. NOT happy! They have been struggling for 2 days now without any luck.

Do the sensors have to be set up/ adjusted/ unit reset or anything like that?

In 2 minds whether to call them & demand they take it to a skoda dealer or specialist to sort it. Have been given a new Vauxhall Insignia cdti but really miss my vRS, haven't seen her in nearly 2 weeks. I am worried they might mess something else up on the car.

Any advice would be very appreciated.