Still Can't Play Online

I fell victim to the problem many other people were having for the past week or so, where I would lose my connection to Xbox Live while trying to join a matchmaking game.

A few days ago, I saw that there was a 'fix', which actually worked - for one day. Even today, I still get the error, and sometimes get put into the default playlist. I've only been able to play a few decent matches in the past two weeks, which is starting to get on my nerves. (Most matches that connected were extremely laggy.)

To see if my internet/Xbox was the culprit, I loaded up Reach yesterday. However, Reach worked just fine, as did BF3 on my PlayStation. Also, my NAT is open.

It's sad that my first post on this subreddit has to be a rant, but I want to play so I can post other cool stuff...

So, does anyone have any advice? Or, at least, is anyone else also having this problem persist?