curl --request DELETE \
  --url https://api.pocketflows.com/customers/{id} \
  --header 'Authorization: Basic <encoded-value>'

{
  "id": "<string>",
  "external_id": "<string>",
  "email_address": "<string>",
  "phone_number": "<string>",
  "metadata": {},
  "unsubscribed": "future"
}