I have not received my order but the takeaway shows it's online.

This could be due to the following reasons.

1. Delay due to the takeaway being unusually busy.
2. The takeaway is closed and has not updated their site.

In any case, it's best to try and reach the takeaway a few times before coming to a conclusion. In case you are unable to reach the takeaway, please reach out to the live chat team and they will be happy to assist you with this.