If you did not leave feedback within 60 days of purchase, then yes, it is too late.
However, if the seller left feedback, and many if not most do when they are paid or when they ship, then you can leave a Response to that feedback.
The most effective responses are calm and factual. Avoid terms like "ripped off". Try: "Never received. No refund." or "Purchase lost (?) promised replacement never received." would work better . Calm and precise.
Responses do not count against sellers, but they stand out on a page.