curl --request POST \
  --url https://api.zappfy.io/chat/block \
  --header 'Content-Type: application/json' \
  --header 'token: <api-key>' \
  --data '
{
  "number": "5511999999999",
  "block": true
}
'

{
  "response": "Blocked successfully",
  "blockList": [
    "5511999999999@s.whatsapp.net",
    "5511888888888@s.whatsapp.net"
  ]
}