which one is correct?

[Zoe2008]

Peter refused to pay EURO 200 .
Peter refused the payment of EURO 200

[bhaisahab]

Peter refused to pay EURO 200 .
Peter refused the payment of EURO 200

They could both be correct, but they mean different things. The first means that Peter refused to pay somebody and the second that Peter refused a payment from somebody.

[Rover_KE]

Note that it's customary to write €200.

If the euro sign is not available on your keyboard, write 200 euros, just like you would write $200 or 200 dollars.

Capitals are unnecessary.

Rover