So the interesting question is whether there is any way to get my money back. Paypal, unfortunately, is not help. Their "buyer protection" guarantee only covers tangible items, virtual items are explicitly excluded. Which is probably a wise choice on their part, because virtual property rights are a legal mess.
Just last week I spent $11 on Dungeon Overlord. I obviously wouldn't have done that if I had known that I would be banned from Facebook this week. It is not as if I had bought something which I have already "consumed", rather I bought some long-term advantages for my dungeon (more tiles, more goblins). And by banning me, Facebook prevents me from taking advantage of my purchases.
Imagine you go to your bank and they tell you that they closed your account because they found that something in your original application for that account wasn't conform with their terms of service which you didn't read closely enough. And oh, by the way, as your account is now closed, the bank keeps all the money that was on that account. Obviously you would have legal recourse, and could send them a lawyer to get your money back. The same thing would apply if you pre-paid for a service, let's say a holiday, and then the travel company finds some reason to not give you that service. You would have the right to a refund.
So how exactly would that work with virtual purchases? Is there any way I could get my money back from Facebook? If not, what is the legal argument permitting them to keep my money without giving me access to the virtual stuff I bought? What if you give money to Blizzard, let's say for a 6-month subscription and a sparkle pony, and Blizzard bans your WoW account the next day, can you get your money back? What exactly would permit a company selling virtual goods to deny you use of your virtual purchases, without giving you a refund? Apart from the obvious problem that the legal cost would be far higher than the possible refund, what are my legal options against Facebook?