Trip.com Overcharge on refund tickets. Each tickets charged $315 just on processing fee

I have booked through trip.com for 3 roundtrip tickets before the pandemic to travel from PEK to SEA which costed USD$3000 in total.  While during pandemic period, flights were cancelled but trip.com was unable to make any changes for me since Feb 2020 which was my originally return date.   I contacted the airline directly and made changes 3 times due to flight cancellations and they were willing to proceed as I was their frequent traveller club member.  However, the latest flight which is due to leave in Oct 26, 2020 were cancelled again.  And this time the next available flight were unavailable.

  I have decided after 6 months of waiting and changing, I will need to get a refund of the tickets and repurchase others.  This was when I turned back to trip.com and first they couldn't able to find any alternatives so after days of back and fro email, I went ahead to ask the company to refund the ticket based on the first email that stated the refund amount per ticket was 3663 CNY / USD450.  However, when I ask this company after less than 7 days of this original quote, they didn't honor this amount and said that they will only provide less than 800 CNY / USD 100 per ticket as they need to charge me for refund fees of 2500 CNY / USD 310 each.  So this means that basically they have originally agreed to provide USD1350 refund now became USD$300, a 10% of the original price paid.  In addition, the company threatened me that if I did not make a decision then the charges will go even higher, bringing down the final refundable amount even lower. 

I believe this is absolutely an unethical practice and while all airlines have been very flexible on changing and refunding unused flight tickets due to the pandemic, Trip.com claimed and accused the airlines were not being flexible while they are the ones who did not honor the rightful refundable amount.  They basically wanted to rip off their customers, especially helpless one who just needed to travel and leveraging this current situation of travel bans/limitations to make customers' lives even more difficult than it is and making money out of every single one of these travelers.