Used stamps exchanges.

Today I got an envelope back that I got on October 26th, 2020 !!! I sent ... with a stamp from Deutsche Post International: No postal traffic with Brunei Darussalam because of the pandemic. Resumption not in sight!
I can just leave the letter lying around, postage it again at some point and send it again.
Two other letters are also missing. This is such a shame because I have only just started the swap and can't get any more swap partners.
Does anyone have any advice?
Thank-you! Chris

Hi! You can keep the letters prepared if the post office don't accept them and send them when it will be possible again.
If for some reason you want to cancel an exchange, you can do so once every 30 days. The slot goes back to your partner and you can request a new address. If you have a canceled exchange with a user, you will not get the address of that member again.