worst service ever!!!

My mum went into pick n pay verulam about 2 hours ago. She purchased some items, one item was on her till slip which she did not buy and it was not in the packet, we phoned to query and we was spoken to as if we are rogues. I hope that the conversation was recorded because I want this to be investigated, we was spoken to very rudely and as if we are illerate! We was charged for something we did not take. I want feedback as to what will be done!!! Been shopping there for forever shocked by the way we were spoken to. What happened to customer service???