At the age of two, many children think "What mine is mine, what yours is yours". Unless they are told otherwise they will never learn.
A lot depends on the development of the child and 28 month old children langauge skills vary lot. It is hard to tell off a child who has next to no speech. However if the child has reasonable language skills then they might comprehend a telling off.
If it had been me I would have taken the toy back to the shop with the child. I would have apologised to the staff with the child watching and listening.
Sometimes actions speak more than words.