Internet with another one than fizz

Yemka

Does fizz charge me my internet data as if it would be fizz when I use my internet home which is with another company?

Zenthar

Fizz would will only "charge" mobile data when done over mobile network. When over home or public wifi (whether Fizz or not) it won't. That being said, some mobiles such as iPhone can use both simultaneously unless that feature is disabled; if the home wifi drops, looses internet access or the signal is very weak, the mobile might switch to mobile data automatically too. So wifi usage doesn't count toward your mobile data, but your phone might use it without you noticing.

StefanM

As long as you are connected to Wifi, mobile data is not used (unless the connection is weak). So you should be fine :)