Chantel Jeffries -- Life with Justin Bieber Sucks ... and I Didn't Stab Anyone

Justin Bieber's new chick is pissed about reports claiming she has a string of arrests in her past ... and has one big regret about hanging with Bieber in Miami and Panama -- it's exposed her life to the world ... warts and all.

Chantel Jeffries -- who was in the Lambo the night Justin was cuffed -- tells TMZ, "I have not been arrested five times as has been stated in the media, nor am I guilty of physically assaulting anyone, in any way shape or form."

A NY newspaper reported 21-year-old Chantel has a lengthy rap sheet, including busts for assault with a deadly weapon (a knife) and reckless driving -- 92 mph in a 70.

Her attorney Matt Morgan tells us ... Chantel was arrested when she was 18 for a misdemeanor assault, but it was ultimately dismissed due to insufficient evidence. Other than that, he says she's only had "traffic violations."

Chantel also denies being thirsty for publicity, saying ... "I am a full time student who had enjoyed a normal lifestyle, free from public scrutiny and criticism, until now.

She adds, "What has happened to me is wrong."

Presumably Chantel means the media attention, and NOT ... joyriding in a Lamborghini, and flying by private jet to a Panamanian resort with an international superstar.