Provider sets priority for cellular data

Hi guys!

I have a weird situation. Recently changed my contract from individual to corporate contract.

Now when I'm i.e. at home my iPhone keeps using the Cellular data instead of switching to Wi-Fi. So I manually have to go to the settings menu and turn off Cellular data and only then wi-fi automatically connects. Didn't have it previously on private contract.

I actually called provider and explained the situation and they said that it is a NORMAL (!!!!) behaviour and I do need to switch it manually all the time.

Do you think it is hardware issue or provider related (sim programming i.e.).

Thank you