Unacceptable advertising & service from Takealot

On Monday I received the usual email from Takealot advertising their products. I was keen to purchase the Toshiba Canvio basic 2.5 external hard drive with 2TB for the advertised price of R750.00. I then placed the item into my Wishlist and upon doing noticed that the spec had been changed to that from a 2TB to a 1TB. I sent a mail to Takealot & attached the email that advertised this specific hard drive but they insisted that they wanted a link. I sent that to them and they answered the next day advising me that the special was only for the day. They did not explain why the spec of the item had changed when I placed it into my Wishlist. I responded by saying that the reason why I did not purchase it on Monday was because the spec changed form a 2TB to a 1TB when I placed the item in my Wishlist. I think that this is totally unacceptable & request that they allow me to purchase the 2TB external hard drive at the advertised price of R750.00