What recourse do I have after buying an expensive stove/oven that does not work?

You could sue the store for fraud.  Fraud is the misrepresentation of a material fact made with knowledge of its falsity and with the intent to induce your reliance upon which you justifiably relied to your detriment.  Here, the store falsely claimed that stove/oven worked properly even though the store must have known the ventilation kit was missing and that the stove/oven would not work without it.  You relied on the store's misrepresentation that the stove/oven functioned properly to your detriment; otherwise, you would not have purchased it.

In addition to a cause of action (claim) for fraud in your lawsuit, your lawsuit could also include separate causes of action (claims) for breach of implied warranty of merchantability and breach of implied warranty of fitness for a particular purpose.  The implied warranty of merchantability means the stove/oven was of a quality acceptable in the trade.  The implied warranty of fitness for a particular purpose means the stove/oven was fit for its designed purpose of cooking food, etc.  These two warranties are implied, NOT written.  If there was a written (express) warranty, the language of the warranty will determine whether or not you would have a claim for breach of express warranty.  If you signed a sales contract with the store, you may have a cause of action (claim) for breach of contract.

Your recourse is to sue the outlet--when you buy some good(s), you have a right to get what you paid for, which in this case is a working stove. You may sue them to force them to take the stove back, return your money, and to also compensate you for any out-of-pocket costs or losses you've suffered; you could also settle with them by having them agree to finally repair or replace anything necessary and get the stove to work. You could try suing them in small claims court, where you could represent yourself (no lawyer needed) and where the cases tend to move faster, so that you could get to a faster resolution. On a non-legal front, if this outlet is owned by some larger entity, you could contact the parent, explain the situation and that you're about to take legal action against the outlet, and see if the parent steps in to resolve the situation. Good luck.