True, sounds like that, a cheap phone with a prepaid card you can buy just everywhere in this world, and nowadays even international calls, if you keep them short, are not so expensive anymore.
Likely she is now using TWO mobile phones, one for her real friends around her and another one for her 'online customers'.
I can only repeat, do not send money to women you know only by internet, even if you see them live on your monitor screen, even if you call to them using a real phone number and not an APPS like LINE...
-----
About Ukraine, - now it is surely not the best time to travel there, but Ukrainian women are not restricted to walk over the border to other countries, like Romania, Turkey, etc.
I can only say, what I would do, just my opinion if I were in the situation of Tsar -
I have the money to try it out as I am curious what might happen...
I would first of all think of myself and arrange 14 days vacation in a nice place of one of the neighbouring countries. Personally (as a native Austrian) I would choose maybe Hungary, Debrecen or Slovakia, Kosice (both are not far away from Ukrainian border with open border check points). I would tell her to show up and call me after she is passing the border and will pick her up.... if she is coming that's fine, nice vacation, no idea how it might develop in future, but I would compensate her AFTER ARRIVAL for her travel expenses - and if not and she does not show up despite her promise, I still have more money left and will enjoy myself and try to meet somebody else....and travel around, maybe rent a car, enjoy good food, hiking around... plenty of other things to do....
If she is really in such bad situation as she claims (and what I do not believe she is) and hopes to meet you in person, she will find some money to show up at the border point, believe me.