Blacberry Classic

Hi

you should not use with Fizz, since is not certified for VoLTE, https://fizz.ca/en/faq/compatible-devices

An LTE compatible phone configured with LTE network preferences must support:

• The HSPA 850 MHz frequency for calls. 
• The dual frequency 1700/2100 MHz (also called AWS or band IV) for mobile data.

A phone that only allows 3G configuration or HSPA network preference must support:

• The dual frequency 1700/2100 MHz (also called AWS)

When you buy a new phone, the supported frequencies are usually listed in the technical specifications. If not, do a search on the Internet. There are sites that will confirm the frequencies supported by your phone once you enter its IMEI in their search engine.