Amelle Berrabah is too scared to turn on her phone after receiving death threats.
The Sugababes singer fled to America after her ex-boyfriend Freddie Fuller's family allegedly sent her a string of violent text messages saying, "You're going to get it".
The 25-year-old star's family is believed to have been given police protection after relatives noticed they were being followed and Amelle's sister Zakiya was beaten up at a petrol station on Sunday (26.04.09).
Amelle - who split from Freddie last month after several heated arguments - and Zakiya were in a taxi on their way to their mother's house in Aldershot, Hampshire, when Zakiya decided to pick up some milk from the local shop.
She asked the driver to drop Amelle off and continued to the shop at the end of the street alone.
As she stepped out of the car, a group of women believed to be related to Freddie jumped out of a vehicle and started punching and kicking her.
An onlooker said: "It was terrifying. One woman got out of the car and allegedly shouted, 'No one drops Freddie,' and then started laying into Zakiya.
"Zakiya was on the floor being kicked and punched by the women. One screamed, 'Tell your family to remember this face!' "
Zakiya was reportedly left bruised and bloodied and later gave a full statement to police who are investigating the incident.
A spokesman from Hampshire Police said: "We were called following allegations of assault shortly after 7pm on Sunday evening to the Total garage on the High Street in Aldershot. The incident involved a group of women and enquires are ongoing."
There is no suggestion that Freddie himself is involved in the attacks or threats.
Amelle's mother is said to be so terrified she is considering moving away from the area.