I agree, she's plain lying.
I had this a few years ago with a girl I was seeing.
Kept getting calls off this bloke, she claimed it was work.
Fair enough, it was a work mobile, but he didn't just ring in working week, in working hours.
Calls late at night, on the weekend. Then she started claiming they were "friends".
She wouldn't answer the phone to him when I was around either.
Suspicion got the better of me eventually & I checked her phone.
He was texting her about what he'd got up to on the weekend & stuff, nothing sexual.
When I challenged her as to why she didn't answer the phone when he rang, her response was I don't want to speak to him when your around. "I want to be with my man" were her words.
I'd have rather had her answer the phone & chat to him if he was just a friend.
She always answered when any of her
female friends phoned her.
Anyway, I finally binned her, & surprise, surprise within 3 weeks she was going out with him.
I had my revenge though, she's the one I had the blow job off (described in a previous thread about BJ's) & spaffed in her eye about 3 months after breaking up with her (she was also seeing him at the time as well).
Plus I fcuked with both their heads for about 3 months & eventually broke them up. Without them knowing it was me, & because I just wanted to shit on her parade.