A nice young gentleman from Nigeria has offered me a share of £27m?

I have no idea why he is being so kind in offering ME such a great investment, but basically his dad died, poor old fella, and because of the dodgy banking system out there, he can't get access to it, it has to be channelled through a UK account, which he can't open. I have set one up, and sent him £12'000 to cover the fees which their banks stupidly impose out there, to transfer it to me. That was 3 weeks ago. Now he says he needs £12000 more, which I have managed to obtain through family, selling the car etc ... soon to be replaced by a ferrari, I hope. Now he says £5000 more ..... I can't afford it, what shall I do? anyone want in??