In most states there are repair and deduct statutes or case law allowing the tenant after notifying the landlord of conditions necessitating repairs due to a health and safety issue can make the repairs themselves and deduct the costs for such in the next month's rent if the landlord is not responsive to the requests for repairs by the tenant.In your situation, you rented the unit that did not have a working oven. Working ovens (as opposed to having a refrigerator in an apartment) are the norm for any rental of residential property. You ended up spending $625.00 for an oven to replace the one that was not working.It seems that you were entirely within your rights to do so and deduct the $625.00 from your following rental payment.If the rental company continues to threaten you with legal action, you should contact your local landlord tenant clinic about the situation.Good luck.