Takealot credit ******

Hi, on the 19th of December, I had my Takelot account credited because of an order cancellation. On the 20th of December, this credit was used to purchase MTN vouchers until the credit balance was left on 0. This purchase wasn't done by me. The feedback I received after reporting this was that my Takealot account had been compromised likely due to similar passwords being used across different sites. I use a completely different password on all my accounts so I find that very hard to believe. I have always received good service from Takealot but in the last month I have lost my trust and will probably not return to them any time soon.