Order cancellation irritation

Takealot has been cancelling a lot of my orders lately. Not sure if they are over selling their products, but the following has happened.

Ordered a product two weeks ago. Got cancelled. My account got credited. I checked availability of the product on the same day... they are still selling it? Price is now higher. I cannot buy the same product with the refund they gave me, I will need to pay more. Please explain what is going on? Will other people buying the product have their orders cancelled due to over sold products? This is not a very nice user experience and unfortunately, this is not the first time this has happened.