Credit Card Details don't match those of my bank...?

Question

This is just classic! Please can somebody help me as Apple are totally useless at getting back to me despite 'escalating' my issue to higher management and admitting that other people are also having similar problems.
I was using iTunes just fine until Jan 8th, I've also bought a load of stuff from the Apple Online Store. All of a sudden, according to iTunes, my credit card Zip Code "doesn't match the records of my bank". I ring JP Morgan and they assure me that my Zip Code certainly hasn't changed! I try to contact iTunes and I get some pointless and thoroughly unhelpful automated response.
I enter other credit cards and then get told that even my credit card number doesn't match those which my bank have - strange as they are identical to the ones on my bank's card and the ones I'm typing in!
I have heard NOTHING from Apple, they have been useless at dealing with this and despite me being a very long-term and loyal customer. What do I need to do, chain myself to the counter at the Apple Store before I get some attention with this? It was fixed just fine until Apple inexplicably broke it for no good reason?!
What is wrong with these guys? They seem to be happy charging top dollar for everything but don't want to give any service back, can anybody help?
Oh, and about the county thing, I live in Manhattan, NY and tried that old trick (ITMS even suggested it) but it keeps telling me that it knows just fine where Manhattan is and won't let me enter anything else!

Answer 1

Apple definitely seems to be having some trouble with
their music store lately... I've gotten a whole
assortment of error messages over the past 2 weeks.
That sounds almost as bad as my permissions problem:
I get an error message that says i don't have
permission to write to my itunes music folder, but I
do! lol
Good luck!
-Dave
iTMS acknowlegded to me in an email on January 27th that they were having problems:
"We apologize for the frustration that this issue has caused you. Some other iTunes customers have also reported receiving an error stating that the zip code associated with their iTunes account does not match the zip code, that their bank or credit card company has on file."
What can be done? My addresses are clearly the same, my bank haven't changed anything, could it be the iLife 06 I installed which has done something to iTunes? Everything was working fine until then...
Let me know how you guys fare, it's pointless having an iPod really if you can't buy the music - do they want us to have to get it by other means?!
Jaimie