Canada Post - Postal Code formatting breaks shipping rates

-- url of the page with the problem -- : www.habbyjacks.com
-- HikaShop version -- : 3.4
-- Joomla version -- : 3.8.7

When I type in a postal code like:
- V1T3K4 the shipping module works fine.

If I mistype the postal code like:
- V1T 3K3 (which is a common Canadian postal code format) then shipping indicates: Free Shipping.

How can this module be configured to accept only the one format that works?

Thanks.

I am using the following for my regular expression check.

(^[ABCEGHJKLMNPRSTVXY]\d[ABCEGHJKLMNPRSTVWXYZ]?\d[ABCEGHJKLMNPRSTVWXYZ]\d$)|(^\d{5}(-\d{4})?$)

This permits Canadian Postal Codes without the space and American Postal Codes.

- If a purchaser enters an invalid postal code (ie: X1X 1X1) which is supposed to be Canada Post's format but doesn't work with the Canada Post plugin, then they receive a custom error message, however they are STILL PERMITTED to continue with the purchase which indicates Free Canada Post shipping.

It looks like I need a way to prevent the user from entering the incorrect Postal Code format at the time they are entering it, or somehow convert it to the correct format.