As someone who works in retail and has been a supervisor myself, feedback is welcomed and is always taken seriously (well was when i worked at target). That service you got was disgraceful, not to mention a mother with a child having to search for a trolley is just down right unacceptable. You should have tried to include names, or even describe what they looked like that way they knew which staff members to have a talk to but its one of those things all staff will need to be spoken to.

BIG that must have been horrible.