Have not received my laptoo

I order an laptop online that was advertised . I complete the application and the Telkom agent informed me that R200 will be deducted from my bank account before they will delivered. I agree with it. 5 days after payment was deducted I did contact Telkom and ask about my delivery. They informed me that they have no stock and as soon as they received stock they will arranged for delivery. I already have paid in front but have not received my items. I am not happy as I am in need of this laptop How can Telkom advertise a product without any stock