Singer Lisa Maffia, a member of Noughties UK hip hop group So Solid Crew, attacked a hairdresser in a south London salon, a court has heard.
The 41-year-old allegedly scratched Rebekah Groves' arms during the "fracas" after attending the shop in Tulse Hill with another woman in May last year.
Croydon Magistrates' Court heard that the pair had confronted Ms Groves over the return of hot comb hair straighteners which she had been selling on Maffia's behalf.
James Tucker, prosecuting, said Ms Groves had been "backed into a corner" of the shop by the women who had "attempted to grab her phone" as she tried to call the police.
"They burst in (and) were being aggressive with her to the extent that Ms Groves took out her phone and said she was going to phone the police," he said.
"She was alarmed.
"It seems that the phone was grabbed, taken off Ms Groves and that she received scratches to her arms and, she says, was hit a number of times.
"The defendant and the other woman left the shop, taking Ms Groves' phone with them."
Mr Tucker said that Ms Groves had followed the pair outside and had been attacked again by the other woman, who "pulled her ponytail and punched her in the face".
Police attended the scene and later interviewed Maffia, who provided a prepared statement but then refused to comment.
Maffia, who attended court in person on Friday, pleaded not guilty to assault by beating on November 3 2020.
The 21 Seconds singer, dressed in a white shirt and black jacket, was visibly upset throughout the proceedings and was supported by a friend in court.
Giving evidence, Ms Groves said that on the day of the incident her shop was closed to the public but she was doing a friend's hair.
She said the other woman, who has not been identified, had come into the shop first before Maffia entered "aggressively", appearing "frustrated and angry".
"I was doing (my friend's) hair and a black lady approached the door and was knocking on it," she said.
"I opened the door and as soon as I opened the door she stepped into the shop. I was a bit confused.
"She looked like she was stalling because she was just asking random questions. It didn't seem like a sincere inquiry.
"A couple of seconds later Lisa barged in through the door too.
"(Maffia) opened the door aggressively and then walked straight in, no 'hello', nothing, just 'where's my stuff?'"
Ms Groves added that the women had "started to get closer and closer" and tried to stop her finishing her friend's hair.
"I said I was going to call the police if they didn't leave, I didn't know what else to do," she said.
"I was very scared.
"They tried to stop me from getting my phone but I grabbed it anyway and called the police."
The court was played a short video of the incident and heard extracts from the 999 call in which scuffles and shouting can be heard.
Ms Groves said she had followed the pair outside to retrieve her phone and had been "chased into traffic" by the other woman, while Maffia held her phone.
"I was scared for my life because (the second woman) was the more aggressive one to begin with," she said.
"I tried to get to the other side of the road but I didn't make it because my ponytail was pulled back.
"My head was dragged down and at the time I believed I was punched in the face, but now I believe I was kicked."
Ms Groves said that later, as she was giving her statement to the police, she received a call from the other woman who threatened to "burn down" her house and her mother's house.
She added that the incident had been "traumatic" and that she now found it difficult to leave her house.
The trial continues.