Can Galaxus do this?

So during the Black Friday week I bought a treadmill on Galaxus, it was almost 50% off and the delivery time was around 2 weeks.

First the delivery time got extended by a few days, and then today (when I was supposed to recieve the treadmill) I got an email claiming that it's out of stock and they have canceled my order!

I checked on Galaxus and the treadmill is still available, albeit for 50% extra and from a different supplier.

Isn't purchasing from Galaxus and getting a confirmation of the order and delivery date legally binding? Is there anything that I can do, specially that they have wasted my opportunity to buy the product on Black Friday from another vendor at a discount?