pragma solidity ^0.4.25; contract FixedPrice { address public owner; address public endUserAddress; uint public price; uint public durationSeconds; uint amount = 0; constructor(uint _price, uint _durationSeconds, address _endUserAddress) public { require(_durationSeconds > 0 && _price > 0); owner = msg.sender; price = _price; durationSeconds = _durationSeconds; endUserAddress = _endUserAddress; } function payVCService() public payable { require(endUserAddress == msg.sender); require(msg.value >= price); msg.sender.send(msg.value); } }