emirate airline — Overcharged for baggage and agents screaming

This airline is running scam. My sister had a connection at Dubai. He flew from Houston to Dubai and when she went to board on the second leg of the flight, she was asked to pay $350 extra. She showed her receipt that she paid $225 in Houston. The agent told her that was from Houston to Dubai and she needed to pay $350 extra for her suitcase for two hours flight. As soon as she started to reason with the agent, he started to scream at her and insult her. My sister ended up in tears; another agent tried to intervene but the man screamed more and pushed her on the side. Another passenger, recognizing my sister's stress, tried to talk to the agent but he was treated with police and jail time. My sister paid, so she can leave Dubai and now she is another country and she has to return with Emirate but she is going to leave all her clothes and return with necessities and minimal luggage, so this airline would not scam her again. This is fraud and the airline needs to return all the extra money they got from her and they managed to destroy her vacation after seven years. These people are not human but animals. I lost all respect for all Emirate people... No matter who they are. I am in Houston and worried for her now... I hope nothing happens to her, when she return to Dubai to return to Houston. These people are exactly from old ages and let's spread the word, so no one travel with them.