209.45.251.54.in-addr.arpa. 300 IN PTR ec2-54-251-45-209.ap-southeast-1.compute.amazonaws.com.
On Amazon Web Service, they provide ability to get PTR record by fill form Request to Remove Email Sending Limitations on their website. Just fill the form and give explanation and good reason. The customer representative will contact you shortly in 2-3 days regarding your request. Good luck!