Not delivering goods

It’s my husband bday tomorrow, and I decided stupidly to purchase goods from TakeAlot, which according to them all items were in stock and will be delivered by today. Needless to say, once again TakeAlot has let me down, changing the delivery date not to tomorrow but to the 10th!!! When I wanted to cancel order and requested a refund, they advised that they will only credit my account meaning I have to spend my money with them, which I then elected to not cancel the order. Surely that is not legal. They did not uphold their side of the agreement, how can they hold my money hostage? I would have never ordered the goods if I knew it would come a week later, as said, the parcel contains a bday present which bday is tomorrow. I phoned the call centre and they of course were unable to assist. They tried to be helpful and I cannot fault the agent of today at all. I feel sorry that he has to work for employers who cannot deliver what they promise.