Worst case you can close the door then apply a thin layer of silicone caulk around the edge (use your finger to spread it thin). It will waterproof it and keep the door from unscrewing. When it’s time to replace the battery again, you can just rub or peel the caulk off. It’s faster than trying to find and wait for a rubber seal to come in the mail. Probably cheaper too when you factor in shipping.