1. Regarding the Costco return policy, if you want a refund, you will need to take back the entire faucet, not just the broken screw-in sprayer piece. If you do take in just the broken screw-in sprayer piece, the Costco guy will be very nice even when he makes you feel like the total idiot you are when he asks: What is this that you are returning? And you realize what you're holding in your hand is not the faucet.
2. Regarding return to the original Gmail compose page, do NOT use the third-party app extension mentioned earlier. Instead, use either Retro Compose for Gmail or Classic Gmail Compose, both of which are available in the Chrome Store.