If there is a phone attached (or your neighbor is willing to attach one), s/he can do some basic troubleshooting, e.g. is there dial tone, does ***1 give an IP address, does the OBi test number work, can you call out, etc?
Also, see whether the Internet connection is working, if not, try rebooting modem and router. Knowing the states of indicators on modem, router and OBi would be useful.
If needed, a factory reset of the OBi may bring it back to life. This could be initiated by from the phone (if that's working), from the LAN (if that's working) or with a paper clip.
If the neighbor has some technical ability, you could talk him/her through setting up remote management and/or dynamic DNS on router.