Yep I am in the same boat.
My renewal is 1st May 2020
Already qualified for Platinum for 20/21 and got this same extension mail which does not help me for next year.
Booked 3 international flights on DSC in Feb for May,Jun and July. These are some of my main earning destinations / times. All 3 events have been postponed or cancelled.
I called and have been informed that if I cancel/bank the flights, my DSC remains,BUT, ONLY if I rebook AND fly within 12 months of my original booking date of 23rd Feb.
My USA trip in July 2020 to a sales conference, it likely to be cancelled and the next one will be July 2021. So I will loose the DSC for 20/21 and also not have it for that conference in 2022.
All this means that the potential number of flights which I will be able to do in 20/21 is going to be severely reduced.
SO I do hope they come to the party and look at additional help in the future.