Can anyone tell me why my monthly subscription suddenly increase from $15.83 to over $35?! Did I miss some fine print somewhere on registration??

Your discounted plan period is over and now you have to pay in full price. Explore Chronobooks to copy your data between QBO accounts. Once you are ready to proceed, open a new QBO accpunt with discounted plan. You may have a limited time until Feb 26 to utilize this workaround.

https://quickbooks.grsm.io/Canada

Good luck!