Jonathan Brereton, 18, was on bail with a condition banning him from contacting his ex at the time he committed that offence at a house in Kelso’s Roxburgh Street on November 10.
He pleaded guilty at Jedburgh Sheriff Court to making comments of a threatening nature and breaching bail.
Fiona Hamilton, prosecuting, said Brereton had been in a two-year relationship with the woman but trouble followed after it ended.
She explained: “She was in her home address with her new partner when a withheld number came up and she put it on loudspeaker.
“The accused was speaking and he was saying things like he would bring people round to come and get him.”
The fiscal said that threat was directed at the new partner, adding that there were further calls with laughter in the background.
Brereton’s lawyer claimed his client, now of Oliver Place in Hawick, had also been threatened.
Sheriff Peter Anderson told Brereton he had been foolish, rude and bullying, adding: “It is time to grow up.
“Do it again and you will be in serious difficulties.”
A community payback order was imposed, including 40 hours’ unpaid work to be carried out over the next four months.