Online order cancellation

I bought a lawnmower from Leroy Merlin online three weeks ago, based on the 10% discount advertised on their website. The lawn mower was cancelled on the day of the delivery, more than three weeks later. What an absolute waste of my time. This is the third time that my online orders have been a mess. If you can avoid buying from them online, do so. They still have the lawn mower advertised.