Greece Broke

Greece have said that they will not be able to make next €300 million repayment to the International
Monetary Fund (IMF), as 'the country has no money to pay', the Interior Minister announced today.
'The four instalments for the IMF in June are €1.6 billion, this money will not be given and is not there to be given' he explained.
Rather cheekily Greece have their hand out for another €7.2 billion bailout but talks between Athens and its international lenders have stalled over the refusal of the Greek authorities to carry out labour and pension reforms.
My question is, if Greece does fail to make the payment, what is anybody going to do about it? 
The lenders can't fine them or ratchet up the interest, they got no money to pay so financial punishments would be fruitless and sanctions would only reduce the little amount they have anyway so someone, somewhere, is going to have to either stump up the money for them knowing they have little chance of seeing that  €300 million ever again, write off the debt which they will never do or renegotiate the repayments over a longer period of time.
However it turns out, Greece seem to have had their cake, eaten it and gone back for another slice.