Amazon Canada FBM shipping with Canada post.

I’m a new FBM seller on amazon Canada. I’m having a lot of issues with my shipping. Today I sold my second item, and the buyer is from northern Ontario. My shipping fee ended up being almost double what I had in my template.

How can I make my buyers enter their shipping address first and then have the shipping cost calculated based on location?

P.s I cannot do FBA because I sell hazmat products and amazon FBA does not accept hazmat products.