Play:1 not connecting - helping neighbor

Good Day,
My neighbor across the street has two Sonos Play:1 speakers. I am not at her house at this time. I am trying to help her get the speakers re-connected. They were playing fine and then she went away for two weeks to bury her husband. Now, she cannot get her speakers to connect to her wifi network (Comcast modem/router combo). I have followed all of the instructions for rebooting the modem, the speakers, resetting the speakers to factory settings, but nothing works. When we plug in one of the speakers the Sonos app sees the speaker and correctly shows the serial number. It then tries to access a temporary network which turns off the wifi...apparently trying to connect via 4G. It gets a no internet connection when doing this. When we try the older app it connects, but then it tells us that the speaker has the more recent firmware and to use the most current app which we do without success. I have followed all of the instruction on the support pages including connecting the speaker directly to the modem/router with an Ethernet cable. I am not personally familiar with the speaker, but I am relatively versed in computers and electronic connections. If while she was away was there an automatic firmware update would that cause this issue? I/we would appreciate any suggestions you can give. She is alone now and the music is her only solace. Thank you for your help.

Regards,

Ed