As the topic. Is there any other option?
You can better use https://www.discomp.cz/, probably has better price and delivery is to other countries as well.
Only there I do not know how much to pay for the shipment.
yes, unfortunately they will fill price based on filled delivery address afterwards, they dont have it automated. But you can probably ask them in advance.
It seems that https://www.alzashop.com also ships to Poland, but I assume discomp will be better.
Alza does not sell those add-ons only whole units. As said, Discomp.cz could be helpful in this case. Feel free to reach them about the shipping price to Poland.
Ah, I’m sorry, I didn’t notice that the OP wanted extra diplexers.
I placed an order, then I will write here what is the shipping cost. When I get a reply from discomp.cz
I would not recommend Alzashop. Their customer service is very automated, the human staff are incapable of meaningful answers, they just read tickets. We had a Turris Omnia warranty return this summer that lasted two months: Alzashop sent the router back to tech support a couple of times, even after it was repaired, rather than returning it to Poland. They never wanted to provide an explanation as to why they did this.
Maybe it’s question to seller.
I wrote to discomp.cz and got a reply with a link to the payment. The package is already at my place.
Very good! Let it serve well.