Yes, MSN has a major issue right now...but really the primary issue is if you need to make a credit card payment as a result of this not whether they will issue credit. They will credit everyone back. Just pause your campaigns until it is resolved. If you ask, they will call or email you when it is fixed and I have always been called back about issues...their customer service for AdCenter is actually very good despite the system.
I have many $40+ clicks yesterday and spent $2000 in "waste" but that will all be credited back in the end. Microsoft will treat us all fair. If not, tell them so.
It is amazing that no one speaks of the amazing ROI that AdCenter has returned versus AdWords or YSM and the good things they do too - I guess that is not what this thread is about though - stupid me. Yes, the system is not optimal, but it does work, delivers high value traffic, and is a solid alternative to Google and Yahoo.
Once the issue is resolved, we will all see our money. Obviously it is a major glitch so it may take a few days to work out...even as they say it will be fast.
I do recommend pausing everything though as not to max out your credit cards. That is your #1 risk. Great thread to discuss the issue, but I would not worry about getting the credit back in fairness.