Bought a product which they did not even have!

I purchased a bikini on onedayonly. First they were late with the delivery and started panicking and emailing me about the late delivery. After that they sent me an email saying they are going to dispatch it. Then another email about how the dispatch is going to happen a week later. Never happened. They emailed me and told me that they aren't going to dispatch it, they are going to refund me. This was 3 weeks after I ordered it. They could really have told me earlier that they do not have the product. They should not advertise something if they don't even have it! Really unprofessional