You can use this API: https://rapidapi.com/xtwitter/api/twitter288

Hi samjohn,

Thank you for using our service.

You can get results of mentions for a twitter account by passing a value (the desired twitter handle e.g @tesla) to the thisExactPhrase parameter. This will search for all tweets mentioning that tweet account/handle. To load more results for that query, every response contains a load_more_tweets field, supply this value in your subsequent requests.

Hope that helps.