Because a page ChatGPT fetched for that question names them and not you: a review platform where they have more reviews, a roundup they are in, a comparison article, a thread. The engine did not choose them; the page did. The report's citations show which page it was, and that page is the fix.
Find the page
Every grounded answer carries its sources. In Perplexity they are numbered; in ChatGPT they are links in the answer; in AI Overviews they are beside the text. The page that names your competitor is in that list. Usually it is one of three kinds: a review site's category page, a 'best X' article, or a community thread.
Then one of three things
If it is a review site, your profile needs to be there with more than about twenty recent reviews. If it is a roundup or comparison, you either get into it or write the better one on your own site, honestly, against the two names buyers already know. If it is a thread, you cannot write it, but the next one can be answered with your name by a customer.
What does not work: changing your own site to say you are the best. The engine did not read your site for that question, so changing it changes nothing for that question.
Read next
Named instead · Citation · How to get your company mentioned by ChatGPT
Ask it about your own company
Your website, region and work email. The score appears in about three minutes, and the report is a link you keep.