curl --request POST \
  --url https://prod.oneloop.ai/api/v1/customer-billing/refill \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '{
  "workspaceId": "<string>",
  "externalMeterId": "<string>",
  "refill": 1
}'

{
  "billing": {
    "id": "<string>",
    "totalCredits": "<string>",
    "usedCredits": "<string>",
    "allowOverages": true,
    "spendCap": "<string>",
    "createdAt": "<string>",
    "updatedAt": "<string>"
  }
}