As the title suggests, I cannot play single player. Whenever I go to load my data, the game says that it can't load the save file becasue i don't have the Firefight Pack and the Groundside Resistance Pack. I have never purchased any DLC for this game. I have only downloaded the free ones for multiplayer and extended cut. if there is any other info that you need to know to solve this, please let me know.
Try uninstalling the game data for Mass Effect 3 and any DLC you do have (but keep your game save data). Then re-install them and try again to see if you can get the game going. I had a similar problem where ME3 gave me an error message saying that DLCs like Leviathan and Citadel weren't installed (although they were) even though the game worked fine the day before. Deleting the game data and installing the DLC again fixed that for me.
Sorry to hear about this. Unfortunately there's nothing anyone here can do for you.
The AHQ is for "player-to-player" technical self-help and game-play discussions.
We're all just fellow gamers, doin' the best we can...
It sounds like you need "official" support from the EA Game Advisors.
They are the only ones who can resolve account, code, or game/DLC activation (or de-activation) issues.
Contact them using the Help Center.
---------------------------------------------------
After getting to the Help Center and filling out the required information, (Product/Problem/Platform)
look for the "Chat Now", "Call Me", or "Email Now" buttons, not the AHQ "Ask Now" one. (You've already done that.)
NOTE: The options you see may vary depending on your region and the time-of-day.
If you select "Chat Now", be sure you have enough time (at least one hour) to wait before being connected to someone. 
Good Luck!
