The big question is why would they sell it on Lazada in the first place if they know they can not deliver it?
Also why can they delivery it if you pay them direct but can't deliver it if paid through Lazada?
I have bought stuff on Lazada that was delivered by the seller, such as extension ladders.
They probably are just using Lazada to get people to see their stuff but not to actually sell it to them through Lazada so they don't have to lose the Lazada commision. Sort of like getting free advertising.