curl --request POST \
  --url https://api.example.com/v1/ui/purchases/{purchaseRef}/reactivate

{
  "success": true,
  "purchase": {
    "id": "507f1f77bcf86cd799439011",
    "reference": "pur_1A2B3C4D",
    "customerRef": "cus_3C4D5E6F",
    "customerEmail": "customer@example.com",
    "productRef": "prd_1A2B3C4D",
    "status": "active",
    "amount": 9900,
    "currency": "GBP",
    "startDate": "<string>",
    "isRecurring": true,
    "createdAt": "<string>",
    "productId": "507f1f77bcf86cd799439012",
    "productName": "API Gateway Manager",
    "planSnapshot": {
      "price": 2999,
      "currency": "USD",
      "planType": "recurring",
      "reference": "pln_1A2B3C4D",
      "billingCycle": "monthly",
      "features": {},
      "limits": {},
      "meterId": "507f1f77bcf86cd799439011",
      "limit": 5000,
      "freeUnits": 100,
      "creditsPerUnit": 1
    },
    "originalAmount": 10000,
    "exchangeRate": 1.3082,
    "endDate": "<string>",
    "paidAt": "<string>",
    "usage": {
      "used": 150,
      "overageUnits": 0,
      "overageCost": 0,
      "periodStart": "2025-10-01T00:00:00Z",
      "periodEnd": "2025-11-01T00:00:00Z"
    },
    "billingCycle": "weekly",
    "nextBillingDate": "<string>",
    "autoRenew": true,
    "cancelledAt": "<string>",
    "cancellationReason": "<string>",
    "metadata": {}
  }
}