I've just bought a new cup and had a look at the leaflet you get with it (as obviously they are very complicated )
"Health professionals say babies should give up their bottles by the age of one while some even recommend a baby goes straight from the breast to a cup at the age of four or five months."
I'll leave out the rest of the scaremongering about your baby never learning to drink from a cup or getting any coordination unless he has one at the age of four months and just focus on the message about feeding.
Is this worthy of complaint?