i cancelled my appointment for internet installation but received a mail saying i missed my appointm

I don't think anyone on this forum will be able to help you.
You'll have to contact Fizz on the chat for that, I think they have a bug with the work order follow up tool.
Chizz )

You can chat with Fizz by open a help page like this one https://fizz.ca/en/faq/im-unable-log-my-fizz-account-what-do-i-do during business hours: Monday to Friday from 8 a.m. to 9 p.m. (EST), weekends and holidays from 10 a.m. to 6 p.m. (EST).