Google Cloud Pub Sub still sending notifications even after stopping all events for the user

In my node server, I am taking user's gmail inbox permissions and adding a watcher to all of them using google cloud's pub sub.

Here's the code:

async addWatcherToGmailInbox({
    gmailInboxRefreshToken,
  }: {
    gmailInboxRefreshToken: string;
  }): Promise<boolean> {
    const auth = await this.loadAuth(gmailInboxRefreshToken);
    const gmail = google.gmail({
      version: 'v1',
      auth,
    });
    await gmail.users.watch({
      userId: 'me',
      requestBody: {
        labelIds: ['INBOX'],
        topicName: 'projects/<project-name>/topics/<topic-name>',
      },
    });
    return true;
  }

But when user unlinks his gmail account from my platform, I stop the notifications first and then revoke the token. But somehow, I still get notifications in my pub sub subscriber on event.

Stopping notifications code:

async removeWatcherFromGmailInbox({
    gmailInboxRefreshToken,
  }: {
    gmailInboxRefreshToken: string;
  }): Promise<boolean> {
    const auth = await this.loadAuth(gmailInboxRefreshToken);
    const gmail = google.gmail({
      version: 'v1',
      auth,
    });
    gmail.users.stop({
      userId: 'me',
    });
    return true;
  }

My pub sub subscriber event where I'm getting notifications:

const pubsub = new PubSub({
      projectId: <project-name>,
    });

    this.logger.log('Google Pubsub initialized, fetching topics...');

    const subs = await pubsub.getSubscriptions();
    const sub = subs[0][0];

    // Receive callbacks for new messages on the subscription
    sub.on('message', (message) => {
      this.logger.log('Received message:', message.data.toString());

      const data = JSON.parse(message.data.toString());
    });

    // Receive callbacks for errors on the subscription
    sub.on('error', (error) => {
      this.logger.error('Received error:', error);
    });

What am I missing to stop notifications for a user when he/she wants to revoke the token.

Note: I did log the response of stop function. It returns empty body just like it's mentioned in the docs.

You can stop to publish message in topic, but there is still messages in the subscription and PubSub try to deliver them until ack or message expiration. You can also purge the subscription