magento2-payment/i18n/pl_PL.csv I found that this text is translated. Just why does not it appear on the frontend?
Make sure you are in
Make sure you have exactly the right word in
Check in your payment module if you have well the translate function like this :
<?php echo __('The word to translate'); ?>
if all this doesn't solve the problem, you can translate it in database(Translate inline), you can enable it in :
Stores>Configuration>Advanced>Developer>Translate Inline>Enable for Storefront>Yes. More info here