curl --request POST \
  --url https://mainnet.gomaestro-api.org/v1/contracts/subscription/createService \
  --header 'Content-Type: application/json' \
  --header 'api-key: <api-key>' \
  --data '{
  "merchant_address": "<string>",
  "selected_out_ref": {
    "tx_hash": "<string>",
    "output_index": 123
  },
  "service_fee_policyid": "<string>",
  "service_fee_assetname": "<string>",
  "service_fee": 123,
  "penalty_fee_policyid": "<string>",
  "penalty_fee_assetname": "<string>",
  "penalty_fee": 123,
  "interval_length": 123,
  "num_intervals": 123,
  "is_active": true
}'

{
  "cbor_hex": "<string>",
  "tx_hash": "<string>"
}