fix: harden hwid provider payment edge cases

backend/bot/payment_providers/heleket.py

@@ -49,6 +49,7 @@ from .shared import (
     parse_payment_callback,
     payment_failed,
     payment_unavailable,
+    payment_units_for_activation,
     quote_hwid_callback_parts,
     render_link_or_fail,
 )
@@ -469,10 +470,10 @@ class HeleketService(HttpClientMixin):
                     )
                     return web.Response(status=500, text="processing_error")
 
-                payment_units = 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_units = payment_units_for_activation(payment, sale_mode)
 
                 outcome = await finalize_successful_payment(
                     PaymentSuccessRequest(