too bad you missed my post last year about Android Lost.
Your carrier likely will do nothing, especially without a warrant. When my brother disappeared and it was feared he was going to harm himself (and he did) it required a court order from the Sheriff to get them to locate his phone, and that was with our employer authorizing it as it was a company phone.
Since the phone is apparently still connecting via WiFi you may be able to utilize Android Lost to retrieve it.
__________________
|