Game stores should not be retailing online.

I have ordered an item online more than 3 weeks ago and they have still not delivered. I received an sms that an attempted delivery failed although no one came to my house to deliver. Then I received an email that delivery was made which is not the case. Game can't tell me what's going on and the courier said the item was returned to the store and is now out of stock. At this stage I just want my money back. Why do online retail if you don't know how!