Hi,
you appear to be mistaken regarding what occurred.
Liam's phone was damaged so he could not provide details of his return flight from the Philippines so your staff said he could not fly and could cancel his flight free of charge. Clearly they should have given him access to the internet to evidence his return details. Therefore, please refund the cost of the flight as agreed.
This is not the level of service one expects when dealing with Singapore Airlines.
Kind Regards