In my plan I have unlimited messaging. However, I'm not able to receive any messages.How can I fix this?

Is your APN properly configured?

https://fizz.ca/en/faq/what-are-fizz-network-settings-apn

What is APN?

Your Network settings. Take a look at the link in my first message.

Did you just activate your account. I just activated one sim today and didn't go through, need use facebook messenger and push them to do something in their end, it works fine now, both incoming and outgoing text plan.

Besides looking at APN parameters, you may also try restarting your phone (equivalent to reboot).

If APN parameters are good and restart of phone did not fix the problem, contact Fizz via Facebook messenger.

I had a problem like that it takes time if not u should try to contact them