Okay, Bubble, first - so sorry this has happened.

I understand the emotional side of this as vmk is a social circle that we all have come to love for various reasons. The friendships and laughter shared in game are amazing.
That said, you need to remove yourself from that completely and view this only logically so that you can see what has happened, why, and how to approach it to find a way to get your access rights back.
I have read the above and would like to try to offer a view that will hopefully help you pull together the facts needed when you speak with someone associated with VMK tomorrow.
So...
Apparently I have been banned for "buying and selling items." I sent in a contact us form yesterday because two Holiday cards' codes would not work. I had puchased the cards off Ebay for a close friend who collects Disney pins, cards, and memorabilia. He does not play on VMK, so he allowed me and my DH to use the codes. Due to a glitch with my wireless, two of my codes would not go through. I wrote into Contact Us explaining the situation and they sent back two replies. One with how they can ban you for selling and buying items and accounts (even though I clearly explained this is not the case) and another saying they can do nothing with things puchased outside of Disney parks and stores (never mind that the cards were in their original packaging -_-)...
...They gave me a lecture about buying/selling items and accounts, and that appears to be why I was actually banned.....
Okay... so, quite clearly, FROM VMK'S VIEW:
You bought cards on ebay, along with codes. From the VMK House Rules:
"#10 Don't buy or sell accounts or items. We reserve the right to cancel any player account that was bought or sold, or player accounts that have bought or sold items." I would have to say that codes most likely is the same as items in VMK's view (not ebay's, VMK's). So... FROM THEIR VIEW, you have broken this house rule (I am guessing).
Now...
...having seen some VERY well known Vmk members selling ACTUAL virtual items (Inferno, Eye pin, stitch) on Ebay, I believe there is a huge difference between that and what I did. I was not even expecting to use the codes.
VERY TRUE. We all probably know people who have bought and sold VMK items on ebay. The challenge VMK has, of course, is how to patrol and when to enforce. Sadly, you told them straight from your own Contact Us message that you bought cards on ebay and attempted to use the accompanying codes. So, you made it very easy for them to decide to enforce this policy against you. Technically, you bought codes for items on ebay.
However... what about intent?
...While yes I did purchase VMK collectable cards, I was not getting them with the intent to use the codes, even though that is allowed and I have done that once in a while in the past for various park quest items (once again, bought the cards, not the virtual items). It is the selling and buying of actual virtual items that is not allowed.
What you need to explain, calmly and rationally, to someone at the phone numbers you have been provided is the order of events and the intent behind your purchase:
1. You purchased the cards.
2. You gifted those cards to a friend.
3. You were then GIVEN codes by your friend, who does not play VMK.
It is a fine line, but there is a difference. THAT is your "leg to stand on." You need to show them that you did not buy codes or items on ebay. You need to get them to see that you bought cards on ebay and a friend gave you some codes as a gift (they just happened to be the codes on the same cards that you purchased). I don't know how successful you will be with this, but from everything you have explained, and hearing 1.5 years of "banned" stories, this seems to be the best approach.
I hope this helps in some way. Please know I am trying to offer you a perspective that hopefully will help (or I would not have spent way too much time following your chain of events and trying to find a way for your present your case).
Two small side notes:
1 -
...they said about the entering too many codes thing, that they do not allow third party software use to enter codes.... what absolute (words i cannot say here, but am still thinking quite clearly in my head)
It truly seems that this is NOT the issue with your ban, but just so you know it IS against the VMK values to use any software at all to enter codes. From the vmk values: "#1 - Use ANY hacking, scripting or editing program that modifies VMK or changes the game. (This includes the use of code generation tools.)"
2 - It seems this began when you wrote to VMK about the codes not working. Sadly, since you do not know the history of those codes for an absolute fact, they may have already been used. Since you mentioned "original packaging" I am guessing they are stitch cards since they come in a little package. Maybe, the codes were already used and the person truly was just selling the cards. No clue, just a thought.... However, the "validity" of the codes would seem questionable to me since you do not know their "life story."
PHEW! Okay... hope this perspective helps you put together some thoughts and an approach when you speak with someone at VMK. Best of luck to you. Hope to see you in Funville soon!
- Dreams