I booked two United tickets via Chase Travel, just wanted to earn 5% cashback with my Sapphire card. It was $6600 each, economy, from SFO to PVG (I know, it is insanely high, but this is what it costs now due to the Covid outbreak). Then last Saturday, it suddenly dropped to $2200 for some dates. So I wanted to cancel mine and rebook, since they were non-refundable tickets, I can only get the credit. But I noticed the Chase Travel's rule "When using this airline flight credit, your credit card will be charged for any fare difference. When you rebook online or through a Chase Travel Specialist using your airline flight credit, if the new flight costs less than this credit, the remaining credit value will be forfeited." I was hesitated to proceed.

Then I checked United website, they did not mention this rule, so I canceled there and got the credit. Then I tried to rebook on United website, but found I could not apply the credit at all. It said "You purchased this ticket through a third-party agency, so we encourage you to contact the original ticketing agency to make changes. Changing your flight here may cause you to lose any discounts applied by the agency, and you won't receive a future flight credit if your new flight costs less than your old flight." So I called United, hoping to get some help applying the credit. The agent was super nice, he even offered to convert the credit to certificate, however, he did not succeed, because I booked the travel through Chase Travel, and I can only go back to Chase to apply the credit. Then the $2200 tickets were all sold out, it went back to $6600.

I could have gotten $8800 credit if I booked on United website from the beginning. But now I am screwed. This is a huge amount, I feel really sad. Don't book from Chase Travel ever!

Now my questions are, is it really the case that United could not do anything about the credits if I booked from Chase?
Could Chase make any exception to give me $8800 credit for future use instead of forfeit it when I rebook (assuming there would be $2200 again)

Thanks!