Task: Get email on Chargebee payment failure

n8n workflow JSON:
{"nodes":[{"name":"Chargebee Trigger","type":"n8n-nodes-base.chargebeeTrigger","position":[250,500],"parameters":{"events":["payment_failed"]},"typeVersion":1},{"name":"Mailgun","type":"n8n-nodes-base.mailgun","position":[450,500],"parameters":{"text":"=Customer: {{$node[\"Chargebee Trigger\"].data[\"content\"][\"customer\"][\"first_name\"]}}{{$node[\"Chargebee Trigger\"].data[\"content\"][\"customer\"][\"last_name\"]}} - {{$node[\"Chargebee Trigger\"].data[\"content\"][\"customer\"][\"company\"]}}\nEmail: {{$node[\"Chargebee Trigger\"].data[\"content\"][\"customer\"][\"email\"]}}\nCountry: {{$node[\"Chargebee Trigger\"].data[\"content\"][\"card\"][\"issuing_country\"]}}\n\nAmount: {{$node[\"Chargebee Trigger\"].data[\"content\"][\"invoice\"][\"total\"]/100}}","subject":"Subscription Payment failed","toEmail":"","fromEmail":""},"credentials":{"mailgunApi":""},"typeVersion":1}],"connections":{"Chargebee Trigger":{"main":[[{"node":"Mailgun","type":"main","index":0}]]}}}