will my wife be stopped from leaving China until this issue is resolved?

My wife ( Australian citizen, living in China) recently traveled to Vanuatu for a holiday ( 12 days). She took with her a mobile phone that had a china telecom pre-paid sim in it ( with several hundred RMB credit). Upon returning to china her phone no longer worked. When a local inquired on her behalf to china telecom they verbally advised the phone was locked due to "over due costs" of in excess of 10,000.RMB.
The telcom company is unable to provide detail regarding the cost & while she was away the phone had very minimal use ( three occasion & very short duration's).