Worst online shop ever.

I ordered my son's Christmas gift 2 weeks ago because it was on special. I used Payflex as a payment option because I het paid every week. After already making 2 payments of R900 they send me an email saying they don't have the item in stock anymore. I tried to contact them and have sent numerous emails with no success. I want my money back. They should have told me when I tried to order that the item is no longer in stock instead of taking my money. This was my fisrt time ordering and will also be my last time.