[Sector-9]

Unless they've retrieved live data from the ABS ECU then how do they know they've replaced the correct sensor/bearing? Sounds like they're letting you pay for their guesswork. Firstly, if the light only comes on once moving then the sensors and ECU are (electrically) okay and unlikely to be the fault. Secondly, if your speedo and cruise control still work then you can forget the front sensors. The most common non-electical problems are failure of the magnetic ring on the rear bearings or interference with the rear sensors from flakes of rust. There are loads of recent posts about ABS faults with lots of good advice and test procedures so search out some of those