Ring Alarm mobile carrier weak singal in Canada won't connect to Canadian mobile carrier stuck on at&t

My ring alarm is stuck on at&t and am in Canada this is the second ring base station and it hasn't fixed the issue I've moved the base station around the house and nothing as happend I've restarted it and still nothing I don't know why but if it sees one bar of signal strength that it won't switch to a Canadian cell tower and stay on it? Sorry but it's not really safe if my power and internet go out