Retrieve a BillFacades: pos, merchantOverview Retrieve a bill by ID. Parameters ParameterDescriptionbillIdThe ID of the bill to retrieve. Example PHP (Merchant Facade)PHP (POS Facade)$retrievedBill = $bitpay->getBill("3Zpmji8bRKxWJo2NJbWX5H"); $retrievedBill = $bitpay->getBill("3Zpmji8bRKxWJo2NJbWX5H", Facade::POS, false);