False advertising

Good day

I have ordered an item from online auto styles...they told me that I should send payment confirmation within 3 days which I did..today I received a call from one of their consulted saying that they don't have the stock that I have ordered ...but how come because they should have told Me before accepting the order..now they want to give me something I didn't order ....I will like you to assist me regarding this matter..

Thank you. George