Unable to switch subscription

[Katiekins198]

I recently switched to Canada/US/Mexico for a holiday, now it won't let me switch back to a regular account.

[slusagm]

it is not that you cannot change back to regular Canada only plan, but it usually just harder to downgrade.

if you see a cheaper Canada US Mexico plan, change to it first.  

Or if you don't see any plan to downgrade at all, you will have to keep checking and some cheaper plans will come eventually

[Yummy]

You can change your plan to plans available on your account ONLY!
If desired plan is NOT visible on your account that means it is NOT available to you and even talking to agent you cannot get it.
Some plans are available to NEW customers only and sometimes some nice plans are offered to existing customers.
In most (all) cases downgrading plan is NOT possible so to get cheaper plan will involve closing current account, losing number and subscribing again (+ cost of new SIM).