There is only one way you can change a wheel bearing, fair enough with the wheel off play wont be easy to spot but when I was on the tools if a motor came in needing a wheel bearing the first thing I would do is make sure it is actually a wheel bearing it needs, its common practice, during this procedure of checking for play in a wheel bearing any play in a tractor joint would be immediately noticeable, any mechanic worth his salt will do this check and relay his findings to his boss. I cant see them thinking the customer would be doing the swivel, that means the customer would be partly stripping down the hub anyway to check the pre load.
This is one of two things as far as I can see, lack of communication or the garage is needing the return work.