Answered question
can i activate my sim through the sim card number?
See the back of sim card, there is long numbers. Send it to Fizz and ask for activation code.
Other answers
I don't believe you can. Maybe Fizz support team can find out the activation code for you with the SIM number.
pretty sure you can't you will need to contact them to get the code again
Message Fizz on their chat bubble or FB.