Xbox Live Gold vanished with 6 months left

Hello,

I have never heard of that happening. I would give XboxLive Support a call. You it is a lengthy process at times but they should know what happend.

Also, if you don't know this already, you only need one account with Live on your xbox and the rest of the profiles will share the same Live subscription.

You should be able to login to the account through Microsoft.com, and view all current and expired XBL subscriptions, please report back your findings.

If the code was acquired legitimately (I'm not suggesting it wasn't, just as a potential), it's possible that it got swept up accidentally. I realize you're having issues contacting Microsoft, but that's your best course of action to get their reasoning
and possibly reverse it. Sadly all I can say to that is keep trying.

If the code was obtained illegitimately, then it's possible that it was detected, and Microsoft would have revoked it. If this happened, then whether it was purposely acquired illegitimately, or accidentally, you're unlikely to get it back, but the same
route of contacting Microsoft would still be the way to go.

It happened to me once i just called up microsoft and explained what had happened

Microsoft/xbox support is your best bet. If you cant get hold of them via messages, try calling?