Ok for all who are having this issue, you will appreciate this.
I too fell victim to this scam, and was determined to get my money back. Here's how I did it.
Go to Xbox Live support site and login. Click support > contact us > unauthorized charges. Not all options will give you the que for requesting a service call, so make sure you pick these ones.
You will then be given the option to request a call from microsoft. Enter your cell number and be sure to keep your phone near. It took them 15 min to call me.
When they call it will have you press 1 to connect. when you get the first agent, CALMLY but STERNLY explain what has happened and how this company is ripping people off by selling stuff on the marketplace that they know doesn't work and renderes the game pretty much useless, and that you want to know how to get your money back since you cant use the DLC. I also threw in that this is an ongoing problem which is discussed on the developer forums, which seemed to add to my case further. The agent will tell you you have to talk to their tech support first before they can refund you, and you will be on hold again for a while. They want you to hang up, so don't. 20 or so minutes later, you will be connected with a higher up agent. Tell them the same story of what happened, and they will ask you to delete everything and try reinstalling, at which point explain that the developer has already admitted it is their fault for how they designed the game and that deleting or buying all DLC are the only options (they will understand that this is very scammy). The agent will put you on hold to research and verify everything. When they come back and offer the refund, you will have to delete the DLC, but who cares since you can't use it. At the end of repeating my story and several holds, I got my microsoft points back, and so will you. I still have 1900 microsoft points sitting around for no reason, but for me it was the point I'm not giving away money especially to these lazy developers or anyone who tries to scam money out of customers.
They know that Activision is doing this, and they just want to see how many people are serious enough to demand their money back and wait on hold for it. So go, do this and tell them what you think of Activision (but be courteous and don't curse, and don't blame Microsoft). If enough people call and complain about this and demand refunds, it will come back on Activision through their contract with Xbox Live, and they might get off their arses and start giving a crap once again about making quality products for their fans.