2011 Volvo C70 - AC not relaible

the air conditioner works sporadically. sometimes working and other times not.

You need to take it in for service. Preferably an AC specialist. This is not a DIY job!

It may have a Freon leak and/or be low on Freon.

Definitely take it to a shop,

That’s an indication of a malfunctioning expansion valve.