same situation as my maid, this is the first time i hired maid, in the first month, she already sms while taking care of my baby, I found that out and then talk to her at that night face to face very seriously. Then she never do it again lar... this is her first time to HK also. You must tell her that you mind this a lot, I told her that she must be 100% concentrate on my baby as this is about safety. She may improved after you told her that. Better tell her asap, otherwise will become worser.