Retrieve an InvoiceFacades: pos, merchantOverview Get a specific invoice by ID. Parameters ParameterDescriptioninvoiceIdThe ID of the invoice to retrieve. PHP (Merchant Facade)PHP (POS Facade)$invoice = $bitpay->getInvoice("QrPWSMkq594kQfJex28S7X"); $invoice = $bitpay->getInvoice("QrPWSMkq594kQfJex28S7X", Facade::POS, false);