I am sorry to hear that you guys and I am sure THOUSANDS OF OTHERS are not having any luck solving your problem, by deleting the .plst file from your library. You have my sympathies. I spent well over a month this summer having the endless conversations and emails with Itunes Support, begging them to send me the redemption codes (which other had reported solved the problem) and having them continue to insist that this was not a real solution and therefore they wanted more time for their engineers to figure it out.
Finally, 2 weeks after SAUL posted his .plst solution on another forum, https://discussions.apple.com/thread/3201787?answerId=16174450022#16174450022 I found the post and tried it and it solved the problem on my MacBook Air. I thought we had found the universal solution, but apparently, given the fact that at least 2 of you have reported here that that does not clear up your problems, this problem still is in need of a universal solution.
It is pretty clear by now, from all the posts in this and other APPLE user forums dealing with this issue, that the redemption code solution has worked for everyone, and this ought to be the way APPLE handles this routinely.
During my long oddysey this summer, I not only escalated to Customer Relations, but I got in touch with the OFFICE OF THE CEO. I have to say that they were both sympathetic to how I this problem was (mis)-handled, and I had a long discussion about how APPLE SUPPORT is NOT handling this very well and what they could do about it. When I heard that a couple of you were being given the redemption codes without your having to go down on your knees, I assumed that APPLE had finally gotten the word out to all support people and this would be the quick resolution to anyone with this problem;
APPPARENTLY I WAS WRONG. Some of you are still being given the run around. I agree this is OUTRAGEOUS. For my part, I will be in contact with my contact in the CEO's office again, direct him to this forum, and ASK ONCE AGAIN, that they get on the stick and make these darn redemption codes available on the FIRST CALL by anyone who needs them!!
Let's keep posting here, I do believe that at least a couple of executives, who do have the power to make executive decisions, are or soon will be looking at this forum.
Hang in there guys,
I know they will make this right!! (At least I hope so.)