Bank Of America Cash Rewards Scam, Internet

In Jan 2011 i opened a Bank of America Cash Rewards Card. For about 20 Month i never missed a payment and always paid at least 2X the min payment. In Sept 13th, 2012 i sent a payment to BoA for the balance on my account. About 10 days later i recieved a letter closing my account due to having sufficient available credit. I had no problem with them closing the account and not account for my 20 month of being a good customer and never complain or even ask to reduce my 21.99% i was paying. My problem is that since my account is now closed i lost my cash rewards balance and it feels like they are actually stealing this money since i earned by using thier card and this also makes me wounder how many other customers went through this same thing. Is it just me, few, hundreds or is it 10's of thousands every time.