Get an invoice

{  "statusCode": 200,  "statusDetail": {    "status": "SUCCESS",    "message": "OK"  },  "result": {    "invoice": {      "id": "inv_jkl012",      "invoiceNumber": "INV-2026-0042",      "paymentNumber": "PAY-2026-0031",      "purchaseNumber": "PUR-2026-0042",      "customerId": "cus_abc123",      "customerName": "Acme Inc",      "customerSlug": "acme-inc",      "customerParty": {        "name": "Acme Inc",        "logoUrl": "string",        "legalName": "Acme Incorporated",        "email": "ops@acme.com",        "phone": "+1 415 555 0100",        "website": "https://acme.com",        "taxId": "US-EIN 12-3456789",        "addressLine1": "500 Market Street",        "city": "San Francisco",        "state": "CA",        "country": "United States",        "pincode": "94105"      },      "orgParty": {        "name": "Acme Inc",        "logoUrl": "string",        "legalName": "Acme Incorporated",        "email": "ops@acme.com",        "phone": "+1 415 555 0100",        "website": "https://acme.com",        "taxId": "US-EIN 12-3456789",        "addressLine1": "500 Market Street",        "city": "San Francisco",        "state": "CA",        "country": "United States",        "pincode": "94105"      },      "purchaseId": "pur_ghi789",      "stream": "ADVANCE",      "planId": "plan_growth",      "planName": "Growth",      "planType": "WALLET",      "plan": {        "name": "Growth",        "type": "WALLET",        "hasWallet": true,        "hasCredit": true,        "hasOutcome": false,        "hasUnit": false,        "kind": "FLAT_PRICE",        "billingCycle": "MONTHLY",        "cost": 499,        "currencyCode": "USD",        "spendingLimit": 1000,        "seatScope": "CUSTOMER",        "carryForward": true,        "billingDate": "2026-08-01T00:00:00.000Z",        "status": "ACTIVE"      },      "billingCycle": "MONTHLY",      "cycleIndex": 0,      "lineItems": [        {          "kind": "credit",          "label": "Deep Research credits",          "quantity": 5000        }      ],      "hasWallet": true,      "hasCredit": true,      "hasOutcome": false,      "hasUnit": false,      "amount": 499,      "currencyCode": "USD",      "currencyRateUsd": 1,      "status": "OPEN",      "issuedAt": "2026-07-01T09:45:05.000Z",      "paidAt": "2026-07-01T10:02:00.000Z",      "voidedAt": "string",      "paymentMode": "STRIPE",      "paymentReference": "pi_3Rt8kX2eZvKYlo2C",      "stripePaymentIntentId": "pi_3Rt8kX2eZvKYlo2C",      "autoPaid": true,      "notes": "Cycle 0 — issued at purchase",      "createdAt": "2026-07-01T09:45:05.000Z",      "createdByName": "Priya N.",      "paidByName": "Dana Whitman",      "voidedByName": "string"    },    "plan": {      "id": "plan_growth",      "name": "Growth"    }  }}

{  "statusCode": 401,  "statusDetail": {    "status": "ERROR",    "message": "Invalid API key."  },  "result": {}}

{  "statusCode": 404,  "statusDetail": {    "status": "ERROR",    "message": "No customer with id \"cus_abc123\"."  },  "result": {}}

{  "statusCode": 500,  "statusDetail": {    "status": "ERROR",    "message": "Could not complete the request."  },  "result": {}}