[harleyquinn]

Arion,
I wouldn't just take it away until she pays you, I'd take it away for good! She's an adult with children, therefore she should be responsible enough to keep an eye on how much she's talking and pay for the extra minutes without even being asked. Since she can't seem to do that, if she wants a phone, let her get her own. No point in ruining your credit so that she can gab. JMHO
If she needs one for emergencies, then I'd go with what Johnny said, get her a prepaid phone.