Question about Samsung Book Cover

I purchased this cover with the Samsung Tab A 10,50. I didn't realise until now that it is the wrong size and I should have ordered the cover 10,50. Surely someone could have helped when I ordered the tablet and cover to go with it. I have been trying unsuccessfully to get hold of help from Galaxus. They don't reply to requests for help on "help centre" and they don't answer the phone. A terrible service.