Elon Musk has said that a lower takeover price for Twitter is “not out of the question,” a week after short seller Hindenburg Research predicted a repricing. The social media company said it was sticking to the “agreed” $44 billion price tag.

Musk made the comment at a conference Monday, several days after putting the Twitter take-private on hold over concerns about fake accounts on the platform. He said he believed at least 20% of the accounts on the network were fake, far above the 5% estimated in Twitter’s filings.

On Tuesday, Musk hit out at Twitter CEO Parag Agrawal for refusing to shed light on the number of fake accounts and said that the “deal cannot move forward until he does.”

Musk’s move before the weekend to put the takeover on hold fueled speculation that he was looking to renegotiate the deal. Short outfit Hindenburg last week argued that Musk would seek a lower price than the agreed $54.20 per share one, citing the recent market selloff and concerns about Twitter’s revenue slowdown.

Twitter shares fell nearly 10% Friday and another 8% Monday, leaving them 31% below Musk’s bid.

Tesla’s billionaire chief executive faces a $1 billion termination fee if he walks away from the deal, but Twitter has the option to launch a legal battle to force him to close the transaction.

Musk said a large number of fake accounts may be considered “a material adverse misstatement,” which would free him of the contract.

However, Twitter said in a detailed filing Tuesday that it was committed to completing the transaction on the “agreed price.”