fix: harden hwid provider payment edge cases

backend/bot/payment_providers/platega.py

@@ -45,6 +45,7 @@ from .shared import (
     payment_failed,
     payment_record_amounts,
     payment_unavailable,
+    payment_units_for_activation,
     post_json_request,
     quote_hwid_callback_parts,
     render_link_or_fail,
@@ -303,10 +304,10 @@ class PlategaService(HttpClientMixin):
             if payment.status == "succeeded" and status == "CONFIRMED":
                 return web.Response(text="ok")
 
-            payment_months = payment.purchased_gb or payment.subscription_duration_months or 1
             sale_mode = payment.sale_mode or (
                 "traffic" if self.settings.traffic_sale_mode else "subscription"
             )
+            payment_months = payment_units_for_activation(payment, sale_mode)
 
             if status == "CONFIRMED":
                 if amount_raw is not None: