If you can’t connect it to WiFi anymore, to use the controller to access the software on it that controls the alarm, your only choice would be to do a full factory reset . But without WiFi to set the speaker back up again, I’m pretty sure you’d lose the ability for the speaker to function. 
 

If you have no personal WiFi, I’d go to a friends house and use their WiFi to set it back up after the reset, so you could use it later on without WiFi.