kath,
for off day, it's a must now unless she accepts compensation. anyway, if she really wants an off day then it's ok lar .. she needs a rest anyway. I think handphone is for communication with friends and family back home ... it's up to you .. but she may end up with one behind your back anyway .. so might as well agree to it with your conditions la - no calls during daytime, no sms-ing when work to be done, phone on silent etc.
for me, my new maid is still paying back her loan. I aldy told her that once she finishes her loan, she can use her pay to get herself a phone to sms Indo or friends here.