Sneaky business practice

I'm really upset with sportscene!on the 18th of November 2018, I received an SMS stating that my limit has increased from 5800 to about 7400. I then make my way to galleria sportscene to confirm if this was true. I spoke to the lady that told me to ignore it.

The next day on the 19th of November, I receive an SMS stating that they had made a mistake and I must not worry about the SMS. I make a single purchase at Charles and Keith with my card and it does not reflect an increase in my credit.

Upon paying for my monthly installment, I notice that my total amount of credit is the said R7400 and not the R5800. Who authorized that increase in credit?