Why has'nt the buyer who bought the item opened not as described disputes?

You can thank buyers who keep dodgy sellers in business by insisting on buying when the feedback warns not to, and then choosing not to open disputes 

eBay do not vet listings

a buyer can not be scammed unless they allow themselves to be

You have chosen to buy from many many dodgy sellers who have horrible feedback

You can't constantly choose to support these sellers and then complain about it/blame eBay

stop keeping them in business