And no, not every transformers animated series has had an ending. Transformers Zone ended up getting canned and only the first episode (out of an unknown amount) was released, leaving it unresolved. The same happened with Transformers: Beast Wars II Neo, which just leaves you on a cliffhanger ending. Both are japanese produced, but are still relevent.
No, Neo had a proper ending. Magmatron and Big Convoy stop Unicron's resurrection via Cybertron and finally end the Maximal/Predacon war.