The family of Isaac Hayes has threatened to sue former President Donald Trump if his campaign does not stop using the late soul singer’s song “Hold On, I’m Coming” at his rallies.

A letter shared on social media from Hayes’ family demanded that Trump comply with the request by Friday, August 16. It also demands $3 million in licensing fees for use of the song at Trump’s campaign events since 2022.

“It has come to our attention that you or the campaign have authorized the illegal public performance of the song on multiple occasions during various rallies for your political campaign without authorization from the copyright holder, despite being asked repeatedly not to engage in such illegal use by our client,” said the letter from the family’s attorney James Walker.

“Hold On, I’m Coming” was released in 1966 by R&B duo Sam & Dave. Hayes, who died in 2008, wrote the song with David Porter.

According to Hayes’ family, the song has been played 134 times by the Trump campaign in the last two years.

The letter from Walker said the requested $3 million payment “is a very discounted fee” for the number of times the song has been used. It warned that the family will seek a much higher payment, including attorneys’ fees, if they take legal action against Trump and his campaign.

“The normal fee for these infringements will be 10 times as much if we litigate, starting at $150,000 per use,” it said.

The family also requested that the campaign release a statement on its social media accounts noting that they did not have authorization from Hayes’ estate to use the song.

It’s at least the second time in recent days that the Republican presidential nominee’s campaign has been asked to stop using an artist’s song.

Representatives for singer Celine Dion said Saturday that use of her song “My Heart Will Go On” at a rally was “unauthorized” and had not done with her permission.