Colleague/friend ignoring me

Hi,

Need some advice!
I have a really good friend who is also my colleague for the past 1.5 years. She will be leaving soon and moving back to her home country. We are very close as we talk every day and meet up sometimes outside of work (we are both females in our 30’s).

She was having an argument recently with our manager and another colleague in which I did not get involved but supported her as a friend through it. She had a rough day in work 6 days ago and I tried to reach out to her. I called her to check in with her, texted her multiple times that day to see if she was okay.
She never replied and has not spoken to me since. I’ve seen her be friendly and respond to other colleagues messages (we have a lot of work WhatsApp groups) but just completely ignoring me.

Need advice as to whether to text her one last time or to just leave it?
Part of me feels she is being so childish as she must have it in her head I did something to upset her but rather than speak to me she is choosing to blank me. So should I play the same game and ignore her back? Or do I text her again to try resolve things?

I should add that this is the second time she has done this. I ended up coming across pathetic the first time, kept asking if I had done anything wrong. She never explained why she ignored me that time and I moved on and forgot about it, I don’t hold grudges.

Upset as I would never treat a friend like this. If they did something to upset me I would speak to them about it rather than play this game and make them feel so clueless and in the dark.

Please help!! Thanks.