The social media platform sent a letter to shareholders saying it would hold a virtual special meeting on September 13 to vote on Musk’s offer.
The letter said: “Twitter believes that Mr Musk’s purported termination is invalid and wrongful, and the merger agreement remains in effect.”
Shareholders have been asked to accept an offer of $54.20 cash per share, 37% above Twitter’s current stock price of $39.34.
It comes after the firm launched legal proceedings in a bid to force Musk to follow through with his takeover offer.
Last week Musk hit back, announcing plans to file a counter-lawsuit to stop Twitter’s request to expedite a trial over his planned termination of the deal.
The billionaire’s lawyers filed papers with the Delaware Chancery Court, arguing Twitter’s request to rush the merger case to trial was “unjustifiable”.
Twitter said it had spent more than $30 million to date on expenses relating to the takeover.
Last week, the company reported an unexpected drop in revenue, amid a weakening sales from advertising. It posted second quarter sales of $1.18 billion, well below the $1.32 billion analysts had expected.
The firm made an operating loss of $344 million, while costs and expenses rose 31% year-on-year to hit $1.5 billion.
Tech stocks have haemorrhaged a combined $3 trillion in value since the start of the year, as soaring inflation, war in Ukraine and fears of a looming recession erased the strong gains made in 2021 and prompted firms across the board to slash growth forecasts and cut back budgets.