fix: confusing wording for billing cycle

docs: update screenshots on readme

includes/i18n/el.php

@@ -42,6 +42,10 @@ $i18n = [
     "Weekly"          => "Εβδομαδιαία",
     "Monthly"         => "Μηνιαία",
     "Yearly"          => "Ετήσια",
+    "dayly"           => "Ημέρα(ες)",
+    "weekly"          => "Εβδομάδα",
+    "monthly"         => "Μήνας(ες)",
+    "yearly"          => "Χρόνος(ια)",
     "days"            => "ημέρες",
     "weeks"           => "εβδομάδες",
     "months"          => "μήνες",
@@ -58,7 +62,7 @@ $i18n = [
     "search_logo"     => "Αναζήτηση λογότυπου στο web",
     "web_search"      => "Αναζήτηση web",
     "currency"        => "Νόμισμα",
-    "billing_cycle"   => "Κύκλος χρέωσης",
+    "payment_every"   => "Πληρωμή κάθε",
     "frequency"       => "Συχνότητα",
     "cycle"           => "Κύκλος",
     "next_payment"    => "Επόμενη πληρωμή",