Yeah, I know! I got the same e-mail from them.
But today, they sent me the following e-mail:
"As we approach the acceptance deadline for our MREs/PhD Economics programme we may be in a position to have some additional funded offers.
We are therefore admitting a small number of students with unfunded offers to give us the flexibility of converting these to funded offers if scholarship slots become available in the run up to the deadline of April 15. We are pleased to confirm you have been selected in this group and you can find details of the offer attached – congratulations. "