Saw a call on my girls phone about a month ago now to an ex fling she had, but then the call disappeared on its own? We’ve been together two years

TLDR: she’s lied to me about a phone call to an ex, she is denied it completely up until the end . I don’t see how she can’t know about it. TELL ME IM NOT GOING MAD

Me and my girl have an agreement where we have access to each others phones. I decided to check hers and saw an outgoing call for two seconds to a guy called Lawrence, who she used to fuck a few years ago and who cheated on her and gave her chlamydia.

Now I know that she used to have this number blocked, so first thing I did was check her blocked contacts and ta da the number is no longer blocked. I’ve tested it and the number wouldn’t have unblocked itself after the phone call, so she must have gone into her blocked contacts and unblocked his number herself.

Later that evening (about half an hour later) we were in the car and I asked to see her phone, she gives it to me and I check for the call, and guess what, it’s magically disappeared. When I call her out on it she does nothing but deny that she knows anything about it, and calls me out for making it up. I actually took a photo of the call on my phone and showed it to her when she tried to deny it, and she says ‘I have no idea why that’s there I’m not admitting to something I didn’t do’.

I feel like I’m being blatantly lied to here and it hurts like fuck, do I just let this go? Or should I put my foot down and leave, because In my opinion there is no way she couldn’t have known anything about:

A. How the contact became unblocked B. The outgoing call C. How the call then disappeared after I saw it with my own eyes

She would not admit to anything and this dynamic went on for three weeks where we weren’t seeing each other but weren’t fully broken up. Eventually it got too much and I said enough is enough, get my shit together I’m coming to get it tomorrow and I’ll be gone, you’re a liar.

The next morning she rings me crying telling me she’s made a huge mistake and she lied to ‘protect’ our relationship.

She said this: “In spilt moment I recalled the time he lied to me saying he weren’t messing with his current girlfriend but he had the whole time and lead me on. I felt anger and wanted to confront why he had acc done that as I weren’t his gf and even tho he didn’t owe me anything. I was triggered in that moment as I saw her name. But then I remembered what’s the point I’ve moved on. It was literally just spit of second thing”

She said she feels stupid and embarrassed and regrets lying at all. Even though I gave her the chance to come clean about six times over the three weeks and she denied it all the way until the very end.

Does she deserve to be taken back? I feel like she carried on this lie for way too long and it as huge red flag. I knew I was right the whole time, and all she did for three weeks was lie to me about it.