diff --git a/src/pretix/base/models/orders.py b/src/pretix/base/models/orders.py
index 60f90dac40..a62ed30c0e 100644
--- a/src/pretix/base/models/orders.py
+++ b/src/pretix/base/models/orders.py
@@ -188,6 +188,17 @@ class Order(LoggedModel):
         except TypeError:
             return None
 
+    @property
+    def payment_refund_sum(self):
+        payment_sum = self.payments.filter(
+            state__in=(OrderPayment.PAYMENT_STATE_CONFIRMED, OrderPayment.PAYMENT_STATE_REFUNDED)
+        ).aggregate(s=Sum('amount'))['s'] or Decimal('0.00')
+        refund_sum = self.refunds.filter(
+            state__in=(OrderRefund.REFUND_STATE_DONE, OrderRefund.REFUND_STATE_TRANSIT,
+                       OrderRefund.REFUND_STATE_CREATED)
+        ).aggregate(s=Sum('amount'))['s'] or Decimal('0.00')
+        return payment_sum - refund_sum
+
     @property
     def pending_sum(self):
         total = self.total
diff --git a/src/pretix/control/forms/orders.py b/src/pretix/control/forms/orders.py
index e0489c71fe..e12f7f418b 100644
--- a/src/pretix/control/forms/orders.py
+++ b/src/pretix/control/forms/orders.py
@@ -375,9 +375,11 @@ class OrderRefundForm(forms.Form):
         self.order = kwargs.pop('order')
         super().__init__(*args, **kwargs)
         change_decimal_field(self.fields['partial_amount'], self.order.event.currency)
+        if self.order.status in (Order.STATUS_REFUNDED, Order.STATUS_CANCELED):
+            del self.fields['action']
 
     def clean_partial_amount(self):
-        max_amount = self.order.total - self.order.pending_sum
+        max_amount = self.order.payment_refund_sum
         val = self.cleaned_data.get('partial_amount')
         if val is not None and (val > max_amount or val <= 0):
             raise ValidationError(_('The refund amount needs to be positive and less than {}.').format(max_amount))
diff --git a/src/pretix/control/templates/pretixcontrol/order/index.html b/src/pretix/control/templates/pretixcontrol/order/index.html
index 57b09e7588..4d231ec354 100644
--- a/src/pretix/control/templates/pretixcontrol/order/index.html
+++ b/src/pretix/control/templates/pretixcontrol/order/index.html
@@ -50,10 +50,7 @@
                                 {% trans "Cancel order" %}
                             </a>
                         {% endif %}
-                        {% if order.status == 'p' %}
-                            <button name="status" value="n" class="btn btn-default">{% trans "Mark as not paid" %}</button>
-                        {% endif %}
-                        {% if overpaid|add:order.total != 0 %}
+                        {% if order.payment_refund_sum > 0 %}
                             <a href="{% url "control:event.order.refunds.start" event=request.event.slug organizer=request.event.organizer.slug code=order.code %}" class="btn btn-default">
                                 {% trans "Create a refund" %}
                             </a>
diff --git a/src/pretix/control/templates/pretixcontrol/order/refund_start.html b/src/pretix/control/templates/pretixcontrol/order/refund_start.html
index 54f450957c..f9048c79fe 100644
--- a/src/pretix/control/templates/pretixcontrol/order/refund_start.html
+++ b/src/pretix/control/templates/pretixcontrol/order/refund_start.html
@@ -35,10 +35,12 @@
             </div>
         </fieldset>
         <p>&nbsp;</p>
-        <fieldset class="form-inline form-order-change">
-            <legend>{% trans "What should happen to the order?" %}</legend>
-            {% bootstrap_field form.action layout='horizontal' horizontal_label_class='sr-only' horizontal_field_class='' %}
-        </fieldset>
+        {% if form.action %}
+            <fieldset class="form-inline form-order-change">
+                <legend>{% trans "What should happen to the order?" %}</legend>
+                {% bootstrap_field form.action layout='horizontal' horizontal_label_class='sr-only' horizontal_field_class='' %}
+            </fieldset>
+        {% endif %}
         <p>&nbsp;</p>
 
         {% csrf_token %}
diff --git a/src/pretix/control/views/orders.py b/src/pretix/control/views/orders.py
index 41e34ab60f..8d5e91ddbb 100644
--- a/src/pretix/control/views/orders.py
+++ b/src/pretix/control/views/orders.py
@@ -442,7 +442,7 @@ class OrderRefundView(OrderView):
             data=self.request.POST if self.request.method == "POST" else None,
             prefix='start',
             initial={
-                'partial_amount': self.order.total - self.order.pending_sum,
+                'partial_amount': self.order.payment_refund_sum,
                 'action': (
                     'mark_pending' if self.order.status == Order.STATUS_PAID
                     else 'do_nothing'
@@ -465,7 +465,7 @@ class OrderRefundView(OrderView):
 
             # Algorithm to choose which payments are to be refunded to create the least hassle
             if self.start_form.cleaned_data.get('mode') == 'full':
-                to_refund = full_refund = self.order.total - self.order.pending_sum
+                to_refund = full_refund = self.order.payment_refund_sum
             else:
                 to_refund = full_refund = self.start_form.cleaned_data.get('partial_amount')
 
diff --git a/src/tests/control/test_orders.py b/src/tests/control/test_orders.py
index 56f2b8b47c..471a807607 100644
--- a/src/tests/control/test_orders.py
+++ b/src/tests/control/test_orders.py
@@ -1402,7 +1402,10 @@ def test_refund_paid_order_automatically(client, env, monkeypatch):
 
     def charge_retr(*args, **kwargs):
         def refund_create(amount):
-            pass
+            r = MockedCharge()
+            r.id = 'foo'
+            r.status = 'succeeded'
+            return r
 
         c = MockedCharge()
         c.refunds.create = refund_create