Return Your Defective Phone
There are people suggesting that you should keep your defective Apple product, and buy a thick strong case for an already way too big phone, and live with it. DO NOT DO THIS
Because of what I call "refund court", just take back your phone and get a proper phablet made by someone more experienced. If you take a bent iPhone into an Apple Store, they will accuse you of abusing it, and refuse to refund your money. In the very least, you will get to experience refund court. I've experienced it twice now because of lightening connectors breaking off in my iPad Mini. They tried to charge me 200 bucks to fix their broken off connector. They kept trying even after I showed them the class action lawsuit against them.http://www.seegerweiss.com/news/apple_i_phone_5_lightning_to_usb_cable_charger_cable_failing_prematurely
My suggestion is that if your phone is already bent, try to flatten it out on a table, then return it for a refund. If it isn't bent yet, return it for a refund. Nobody should be told to keep a defective device. Ever. The real issue here is that the weak point is very close to where the battery connects to the board in the phone. This bending issue may not just be merely cosmetic. It could be downright dangerous. Apple tried to make big phones. They messed up pretty bad. Don't reward their failure by keeping their defective product.