diff --git a/plugin.rb b/plugin.rb
index 62962c1..3b8986d 100644
--- a/plugin.rb
+++ b/plugin.rb
@@ -61,25 +61,28 @@ SQL
       isolate_namespace DiscourseSolved
     end
 
+    AUTO_CLOSE_TOPIC_TIMER_CUSTOM_FIELD = "solved_auto_close_topic_timer_id".freeze
+
     def self.accept_answer!(post, acting_user)
       topic = post.topic
-
       accepted_id = topic.custom_fields["accepted_answer_post_id"].to_i
+
       if accepted_id > 0
         if p2 = Post.find_by(id: accepted_id)
           p2.custom_fields["is_accepted_answer"] = nil
           p2.save!
 
           if defined?(UserAction::SOLVED)
-            UserAction.where(action_type: UserAction::SOLVED, target_post_id: p2.id).destroy_all
+            UserAction.where(
+              action_type: UserAction::SOLVED,
+              target_post_id: p2.id
+            ).destroy_all
           end
         end
       end
 
       post.custom_fields["is_accepted_answer"] = "true"
       topic.custom_fields["accepted_answer_post_id"] = post.id
-      topic.save!
-      post.save!
 
       if defined?(UserAction::SOLVED)
         UserAction.log_action!(
@@ -105,23 +108,40 @@ SQL
         )
       end
 
-      if (auto_close_hours = SiteSetting.solved_topics_auto_close_hours) > (0) && !topic.closed
-        topic.set_or_create_timer(
+      auto_close_hours = SiteSetting.solved_topics_auto_close_hours
+
+      if (auto_close_hours > 0) && !topic.closed
+        topic_timer = topic.set_or_create_timer(
           TopicTimer.types[:close],
           auto_close_hours,
           based_on_last_post: true
         )
 
+        topic.custom_fields[
+          AUTO_CLOSE_TOPIC_TIMER_CUSTOM_FIELD
+        ] = topic_timer.id
+
         MessageBus.publish("/topic/#{topic.id}", reload_topic: true)
       end
 
+      topic.save!
+      post.save!
+
       DiscourseEvent.trigger(:accepted_solution, post)
     end
 
     def self.unaccept_answer!(post)
       post.custom_fields["is_accepted_answer"] = nil
       post.topic.custom_fields["accepted_answer_post_id"] = nil
-      post.topic.save!
+      topic = post.topic
+
+      if timer_id = topic.custom_fields[AUTO_CLOSE_TOPIC_TIMER_CUSTOM_FIELD]
+        topic_timer = TopicTimer.find_by(id: timer_id)
+        topic_timer.destroy! if topic_timer
+        topic.custom_fields[AUTO_CLOSE_TOPIC_TIMER_CUSTOM_FIELD] = nil
+      end
+
+      topic.save!
       post.save!
 
       # TODO remove_action! does not allow for this type of interface
@@ -134,14 +154,13 @@ SQL
 
       # yank notification
       notification = Notification.find_by(
-         notification_type: Notification.types[:custom],
-         user_id: post.user_id,
-         topic_id: post.topic_id,
-         post_number: post.post_number
+        notification_type: Notification.types[:custom],
+        user_id: post.user_id,
+        topic_id: post.topic_id,
+        post_number: post.post_number
       )
 
       notification.destroy! if notification
-
       DiscourseEvent.trigger(:unaccepted_solution, post)
     end
   end
diff --git a/spec/integration/solved_spec.rb b/spec/integration/solved_spec.rb
index ed9811a..d6a829b 100644
--- a/spec/integration/solved_spec.rb
+++ b/spec/integration/solved_spec.rb
@@ -41,20 +41,32 @@ RSpec.describe "Managing Posts solved status" do
     end
 
     it 'can mark a post as the accepted answer correctly' do
+      freeze_time
+
       post "/solution/accept.json", params: { id: p1.id }
 
+      expect(response.status).to eq(200)
       expect(p1.reload.custom_fields["is_accepted_answer"]).to eq("true")
 
-      expect(topic.public_topic_timer.status_type).to eq(TopicTimer.types[:close])
+      expect(topic.public_topic_timer.status_type)
+        .to eq(TopicTimer.types[:close])
+
+      expect(topic.custom_fields[
+        DiscourseSolved::AUTO_CLOSE_TOPIC_TIMER_CUSTOM_FIELD
+      ].to_i).to eq(topic.public_topic_timer.id)
 
       expect(topic.public_topic_timer.execute_at)
-        .to be_within(1.second).of(Time.zone.now + 2.hours)
+        .to eq(Time.zone.now + 2.hours)
 
       expect(topic.public_topic_timer.based_on_last_post).to eq(true)
     end
+
     it 'does not set a timer when the topic is closed' do
       topic.update!(closed: true)
       post "/solution/accept.json", params: { id: p1.id }
+
+      expect(response.status).to eq(200)
+
       p1.reload
       topic.reload
 
@@ -63,4 +75,29 @@ RSpec.describe "Managing Posts solved status" do
       expect(topic.closed).to eq(true)
     end
   end
+
+  describe '#unaccept' do
+    before do
+      sign_in(user)
+    end
+
+    describe 'when solved_topics_auto_close_hours is enabled' do
+      before do
+        SiteSetting.solved_topics_auto_close_hours = 2
+        DiscourseSolved.accept_answer!(p1, user)
+      end
+
+      it 'should unmark the post as solved' do
+        expect do
+          post "/solution/unaccept.json", params: { id: p1.id }
+        end.to change { topic.reload.public_topic_timer }.to(nil)
+
+        expect(response.status).to eq(200)
+        p1.reload
+
+        expect(p1.custom_fields["is_accepted_answer"]).to eq(nil)
+        expect(p1.topic.custom_fields["accepted_answer_post_id"]).to eq(nil)
+      end
+    end
+  end
 end