Incomedia, the provider of WebSite X5, is based in the EU country Italy and is unlikely to support payment processing through a Russian bank due to EU sanctions against Russia.

You probably have to find another user of WebSite X5 who has already made the effort with Yookassa and gives tips on integrating it into the shop.

Incomedia's instructions are short and probably difficult for laypeople to implement, see

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How to set up a custom payment method.

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#tip - For more information about custom code, please contact the payment service provider you chose.

>> https://guide.websitex5.com/en/support/solutions/articles/44002275655-so-richten-sie-eine-benutzerdefinierte-zahlungsart-ein-

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Maybe you can find a helper with experience in setting up Yookassa.

M. Smith, Daniel is just a user like many of us and was simply trying to be helpful. You may not have meant your response to sound rude, but that's how it came across. Adding extra payment options is not always straightforward and although we all would like to see Incomedia add many more, you will probably get more help from users like Daniel and others who have had experience in doing this sort of things on their own sites.

Hopefully you will get some responses from those users over the next few days.

В Юкассе прекрасно описаны методы интеграции, вам всего лишь нужно нанять программиста на фрилансе, и он вам напишет код, который вы просто подставите в программу.