If you phone is 8 months old then you purchased the phone when the 30 day worry free guarantee was in place, and if you have had problems with the phone from day one, you should have took advantage of the 30 day worry free guarantee and got a completely different phone.
Like the other poster said, with the manufacturers warranty you always get a refurb phone, even with insurance you get a refurb phone. The only way you will get a brand new phone is through the return policy, purchasing full retail, or if you are approved to get a new phone at the discounted pricing.
I know it is frustrating to get told you will get a new phone, but you really only get a refurb, but going into the store and yelling at the reps will not get you anywhere, trust me. The nicer you are, the more they will be willing to help you. The only thing I can do is just keep returning the phone. My sister returned her Pixi Plus 3 times, and on the 4th time, we spoke with a store manager and they gave her a brand new Incredible with a new two year contract at the discounted pricing, and it was because we didn't go in "guns-a-blazin".
I apologize for any confusion or misconception about the warranty process. The manufacture does provide a Certified-Like-New device at no cost when an issue falls underneath the warranty and requires replacement.
Please PM me your name and mobile number so I may look further into this for you.