Used stamps exchanges.

Austrian Post has suspended its Postal service due to the war in Ukraine.
I can not send letters to Russia and Ukraine at the moment.

Dear friend! You know about the humanitarian situation in my country as a result of the Russian invasion. The school in Lviv, where my children study, now has a shelter for elderly people who have lost their homes in the eastern regions of Ukraine. That's why I have to ask you for financial help. Not for myself ... For those people who cannot exist without such help .... Please ... I will use this money to buy food and clothes that I can donate to the shelter. I am an honest person.
Roman Skabara
PayPal
borakuda1974@gmail.com
Nickname: BorakudaLviv

@snowmark, You can add the mail restriction and you can send me a message with the id of that letter. I will cancel it and in this way it will not affect your slots.

@ Danubius .... good idea, although soon most countries won't let you send to Ukraine.

But, more importantly, what happens when the system allocates me an address in a country to which my postal service doesn't deliver? I presume I will have to cancel, but that shouldn't take up one of my slots.

I have added mail restrictions options. You can view this list and you can sugest changes to it. "Mail restrictions" from the left menu after you log in. If your post office does not accept letters to specific countries you can add them there.

Of my 10 letters travelling at the moment two were sent to Russia, one to Poland and two to Latvia .... might need to be prepared for them to take even longer than normal.

Mail from Russia now
https://www.pochta.ru/assets/Sroki_dostavki_v_24_24022022_3a4b09cbcf.xlsx
(from Russia to Austria for 15-30 days)