Worst online shopping / purchase experience - sold me stock that did not exist

Worst online shopping experience. They sold me an item the they had no stock for. Delivered incorrect stock to my address after a long 1 week wait, then failed to return to the same location to pick up the wrong stock. On the online portal - the order does not even show on my profile to date - order 306964

They eventually after several calls and emails, blamed me for their mistakes and incompetencies in their delivery system and failure to pay attention to detail. 1month later still having a back and forth about the same thing. And I have had to. be manually following up on my purchase and making calls at my expense -- only to be told i should contact their warehouse on my own to get things moving...yet their internal processes should not be my business or stress to deal with --- only now (32days later), they say "we dont have stock" and they declare their refund will take another 10 worming days .....after inconveniencing me and blaming me for their mistakes for over a month.

I am informed I am not the first to experience such - I advise - you would rather not purchase online "if you must use" Leroy Merlin - rather walk into a branch to avoid this ****y service