collectible vs due

collectible and due both are nouns.

Word	Noun	Adjective	Verb	Adverb
collectible	Yes	Yes	No	No
due	Yes	Yes	No	Yes

collectible (noun)	due (noun)
things considered to be worth collecting (not necessarily valuable or antique)	that which is deserved or owed
	a payment that is due (e.g., as the price of membership)

collectible (adjective)	due (adjective)
subject to or requiring payment especially as specified	owed and payable immediately or on demand
	suitable to or expected in the circumstances
	capable of being assigned or credited to
	scheduled to arrive

collectible (adverb)	due (adverb)
	directly or exactly; straight