The UK's competition watchdog is preparing for another round of legal action against ticket reseller Viagogo.
The Competition and Markets Authority (CMA) says the site is still not complying with consumer protection rules, as backed by a court order.
The Competition and Markets Authority (CMA) took Viagogo to court last year for breaking consumer protection law.
The ticket seller was given a deadline of 17 January to comply with a series of changes.
Geneva-based Viagogo told the BBC shortly after that deadline it was "compliant".
The High Court order required it to make a number of changes to the way it collects and presents information about tickets for sale on its site, in particular about seat numbers, resale restrictions and face value as well as to the way it uses messages about the availability and popularity of tickets.
Under the order it must also publish the names and addresses of touts who are selling more than 100 tickets a year from the site.
The watchdog said it had warned Viagogo again it was still not complying with that order, although some improvements had been made.
A statement said: "For a company not to comply with a court order is clearly very serious. We are therefore now preparing to take legal action to ask a court to find Viagogo in contempt."
The watchdog formally raised "serious concerns" with Viagogo in January about its compliance with the order and said it must address them or face a return to court.
If a court finds Viagogo in contempt, it can fine the company or even send senior officials to prison.