Welcome to this user forum.
Does this happen on Ethernet connected devices as well, or is it just wireless connected devices?
Then you need to check with a wired device connected, as that will indicate whether its an actual Infinity connection issue, or simply a wireless problem and not a BT problem.
When you get the disconnection, does the light on the home hub change colour?
Then you need to check with a wired connnection, wireless is not a reliable indication, as there are too many variables.
How can i get the issue fixed then
Its something you will have to sort out yourself, as BT will not be able to help with this.
Try turning Smart Setup off.
Also try separating and renaming the SSIDs.
If its a home hub 6, then separating the SSIDs is called splitting the wireless channels, and is done on this screen.