Raz firstly you have been promised goods that have not arrived unfortunatly 28 days is deemed reasonable time so you will have to wait.
Secondly Please tell me you DID pay with a credit card. if so after the 28 days have passed and you still have not recieved the goods you are within your rights to cancel the order under the sale of goods act as the goods have not arrived within reasonable time. If they refuse to hand back/ credit the card with the money, your credit card company is jointly liable under the consumer credit act. By using that you will get yoour cash back, it will just take a little time. Sorry to hear that you are being messed about as it drives me nuts when compannies do that.