Idk if you managed to fix your problem but I had the same thing. My apple ID on my iPhone 4 changed somehow (now I know why) and my birthdate was input wrong. After months I fixed it last night. Here what I did on my iPhone:
First of all you CANNOT fix it thru you "manage my apple id" page. That will update everything except what you need to fix. Go to =settings = iTunes AppStore = change your apple ID to what you want. Now go to EVERY single app installed on your phone and change it where ever the wrong ID is listed. Don't skip anything. I found the wrong Apple ID associated with my video and camera. Any apps with the wrong ID that you cannot manually change the email/ apple ID you will not be able to download updates, so if you need the update you have to delete the app and reinstall after you finish fixing the problem. Now, this is where I think I inherited the problem: go settings= icloud (it may be listed as the wrong email here) on my phone it is first listed w the apps above Mail. So, it's settings = icloud = account + advanced tap on(your email)=here is you SMTP server, outgoing mail. Make sure you change this to the correct email associated w correct apple ID. Now go back to settings= "mail, contacts and calendars" open your email account (more than one? Do them all) here you will find yourSMTP severs, default email address for your contacts and calendars (if your default here is diff than email associated w Apple ID and you update these it will change your ID again) you can change what needs to be changed. Open the "advanced" link when you find them and update
when you are checking EVERY thing installed on your device follow every "advanced" setting you see and make changes you need, want. Now go delete the apps with wrong ID that will need upgrades installed. Now go open App Store and now is your opportunity to set new security questions and changed that $@#¥!! Wrong birthdate. Hope this helps. Good luck. Ps, my apple ID is my icloud address. I sync'd my hotmail with it on my phone so when I downloaded apps from a site that I put my hotmail as my email, it changed my ID. I'm pretty sure that's how this happened. I have decided to get all my apps from the App Store from now on and not thru sites on the web. Oh, go check your email for any confirmations Apple sends you. Again, good luck
