1) Paid option fee - forfeited
2) 5% downpayment & stamp/legal fees - forfeited
3) Loan - keys not received, not an issue since loan not disbursed yet
4) CPF grants - to be returned with interest. Must download the flat cancellation form from hdb website. HDB will reply you with a letter to authorise the return of the grant from your CPF. Failing to do so will be equivalent to owing money to the govt and you wont be apply to apply for any more flats till you repay