Wifi Calling in the USA

Hi there!

I have been a Telus customer for over 12 years and would love to continue with them... however, I've recently been splitting my time between the USA and Canada and live in a very remote area that has little-to-no cell signal (I get 10+ text messages a day saying "Welcome back to Canada" or "Welcome to the USA" – because I am so close to the border, it is constantly switching back and forth when I get a one-bar signal).

With no reliable signal, I rely heavily on wifi calling but can't make a call when I am in the US. When visiting the city (I go in every few months), I went to a telus dealer and they did something with my sim that helped solved the problem for a month. Unfortunately I am once again unable to make wifi calls. 

Is there anything I can do to fix this? Or do I need to switch to Rogers?

If there is nothing I can do about it and need to switch, how do I contact Telus to cancel my account? I use the chat bot but it keeps trying to book a callback time..... but I cannot receive a call! lol... vicious circle. Is there an email I can use to cancel with Telus?

Any help would be appreciated! :)