How long does it take to have a issue fixed after contacting fizz's support team?

It depends on the problem, usually you will get a first response in the following days.
Sometimes they will fix your problem without telling you they fixed it. Other times, for complex problems, they will tell you they do everything they can to address the problem.

Relax and wait

It shouldn't take longer than a couple of days based on my experience with CS.

It really depends on the issue. The first level will do what they can and will forward it to the next level if needed. From there who knows. I have not gotten any feedback from next level support.

If the answer came from the first level very fast, otherwise good luck

Should be relatively quick.

Just got in contact with them took me 30mins :)

Good Luck, they're not work hard around the clock as mentioned in multiple fizz posts.