Luggage Policy ****!! Save R100 now,pay R250 later

I received a promotional mail from Travelstart, on a promo special FlySafair, and booked my son's ticket online. He paid at the FNB ATM paypoint. Received mail confirming booking, and another later to do online check in, which we did on Friday before flight on Sat morn. Received a mail confirming all good. My son arrived with his 2 gymbag size bags, and was told he must pay R250 for the extra bag. Yes, you are allowed 20kg, but only 1 case/bag.His luggage was not even 12kg in total. He asked to take the smaller 5kg as hand luggage then, they refused. I told him NO WHERE it states such a policy on any of the online screens/emails. He asked them to phone me, they refused. He asked to show them online, they refused. He showed them the emails on his phone, they shrugged.He showed them the contents of his wallet (R60), they insisted he pays R250. He was forced to leave his one bag in JHB. I feel like a FOOL for choosing you, making me feel like a bad mother, putting my son through such an ordeal at his young age, with no understanding, customer service, or compassion shown from your staff, and for deceiving us, your customers like this!!! I will never recommend you!! Such a horrible end