How are they messing you about? O2 have never officially announced when PAYG will be available, it's all been rumours and assumption that it'll be available on the 11th.
By messing about, I mean messing us all about by making the error of leaking information and then pretending it never happened. Keeping the PAYG up but refusing to discuss it and say, for example, we are hoping to provide the service in a couple of months, etc. but can't guarantee it. What does "soon" mean? Absolutely nothing. They are hedging their bets. They'll see how many contracts come forward and then when there are left overs these will be sold to the poor and miserly Pay & Go customers. Sure, they want to make money, but don't treat potential customers as second class. After all, all that upfront cash is not to be sneezed at, even if in the long term the contracts are more lucrative.