I took advantage of the twitter promo as soon as it launched without having bought any credits prior. It set my CPU limit to 50, and I could not change it (I didn't set any limit myself to start, it did it all by itself). It said I would be set for 11 days (I assume after the first day was subtracted). I wanted to lower the limit, but there was nothing I could do, though it said I had -50 credits available. Now my CPU is off, and it still says I have -50 credits. What happened to the rest of credits from the promo?

Will I have to buy the $10 thing to start playing, or will I be able to play solely on the twitter promo (given I don't have a high cpu count etc), and if so, when will it be available?