I checked up on her and she ignored?

[Xenon21]

She has mental health issues. So she is up and down in moods quite often.

She phoned me up the other day after months of no contact and said she missed me. She said it made her sad to stop speaking to me cause her boyfriend asked her to. She said when she hung up the phone, she'll break up with him. I messaged her a few days later saying 'How are you doing? Hope you're getting on alright' to which she didn't reply. I don't really have any intentions to message her again or contact her in any way.

Why wouldn't she reply?

[Jamesshinobi]

because her boy friend asked her not to and she lied about leaving him.

[Lunatic1]

She couldn't bring herself to leave him, so she cut you out again for him.