What's up with the phantom messages on my iPhone?

I recently bought an iPhone 4S and upgraded to the iOS 6 software and ever since I've been getting random tri-tone alert sounds and no notifications. No messages, no emails, no nothing. I've checked everything. I have the double alert thing off, where it only sounds once when I receive a message so it can't be that. I've googled it and the only thing I've found is it could be the google mail or eBay apps, but I have neither of those apps installed, nor downloaded. Is anyone else Having this problem? Someone please help its getting on my nerves!

Go to phone shop

All apps closed? Make sure you aren't running some strange app, press home twice to see the app list then make sure they are all closed out.