Staff share customers person details their friends

I have allowed my mother-in-law to purchase a washing machine on a 24month term, on my game account, she pays every month in Ladysmith using my game card number as I am in Newcastle. 3 February 2016 mother-in-law and her daughter (Reena) go to Game Ladysmith to one of Reena's friends (Cathy) who is employed there. Reena and her mother request Cathy to open my account details using my Game Card Number so the three of them can perusal my personal details and purchase history. From this Cathy gives them wrong information that the washing machine which was purchased in April 2014 over 24 months is \paid off a long while ago\". Among the three of them they all fail to do simple maths and establish that there are still 3 outstanding instalments for the washing machine.I think it's important to mention that when I call into call customer care to enquire about my account I have to answer security questions and when I go into the store I have to produce my ID. So my problem is with Cathy using my game card number to access and share my personal account details and purchase history with her friends without my consent or my approval. And causing them to accuse me of cheating them."