CheapOair cheapoair.com Fraud, won't let me take my return flight Internet

I have booked a return flight for two people, from Guangzhou to London through CheapOair's website. The Philippians airlines flight information during the booking and in the confirmation email contained the statement that the flight was non-refundable, and non-changeable. But I couldn't make it to the departure flight on 6th of August 2018, and I called the customer service and the airline 3 days earlier to inform them about that, and to see if there was anything could be done to change the date of departure by paying extra fees. The CheapOair didn't accept to help at all in the beginning and blamed it all on the airline, and only after I contacted the airlines and got confirmation from them that it could be changed to a later date, they accepted to contact the airline and we had a conference call (airline agent, cheapoair agent, and I) for an hour while I was dialing an international call, trying to resolve the issue, but finally the dates available were not suitable for my traveling plans, and I gave up on the departure flight, but asked to maintain the return flight as it on August 24th 2018 which is non-changeable and non-refundable.

Then on the 6th of August after the departure flight was gone, I went to the airlines office in Guangzhou to secure my return flight as I have booked a new departure flight. Then they told me it was still OK in the system, but it might get forfeited since my departure flight status was "NO SHOW" as they said, while I have already informed them that I was not going to make it, and advised me to ask the agency "CheapOair" to reissue my ticket to solve this problem, and it would be without any extra charges. But after long chats on their website and long phone calls with their agents, CheapOair has refused to help in anyway, after they told me that since I missed the departure flight, my return flight is automatically forfeited according to AIRLINE POLICY. After that no one informed me of this policy, not before the booking, nor after the booking, nor after I called to inform them that I couldn't make it to my departure flight, but until the departure flight was gone already. And after long conversation and arguments, they finally couldn't get rid of me until they told me that some higher manager or supervisor will contact me, after they used up literally every trick in the book trying to decline me.

Later I got one call from someone claiming to be the supervisor, and asked me some questions, then after claiming that she understood my compliant, she said that she needed to check the call record to confirm that their agent never informed me of that policy, to confirm that it was their responsibility and try to do something about it, and she would call me back. And since then I haven't heard from them. There are still 13 days until the date of my return flight, which I paid for, but can not get on, because the people responsible for providing the service are declining to do so. I just want secure my return flight which I paid for and confirmed.