Online service terrible

Worst experience ever. Bought a laptop online. After a week I enquired when it would be delivered. Apparently it was sold out. They offered me another laptop, I had to pay more money in. After two days I enquired when this one would be delivered, apparently sold out again. They then offered me a cheaper laptop, I received this but after two week I'm still waiting for a refund of the extra money I paid. Terrible service.