Lagguage issue

Am I mad? Extremely because FlySafair please explain to me how the 7kg bag and personal item works because 1. My mom travelled from Lanseria, with the same bags a small suitcase and a sports bag, small suitcase was weighed 6kg she was told to go up with all of them, today she is travelling from cpt back home with the same set of bags and she is told she needs to pay R375 as she has too many bags, I mean why when its the same set if bags? Does the rule apply differently from lanseria and cpt international? If so can that be included in your policy because it doesnt make sense as she was told in lanseria she doesnt need to pay for the bag and now she is told the personal item is not a laptop bag and therefore she needs to pay, somebody explain this to me or better yet issue out a refund