wifi connected, but no internet

Hi,

Having an issue with some wireless devices saying they are connected but have no internet access whilst having a mostly full signal. for instance, my phone and pc will both be on wifi in the same room, but my pc will say no internet access whilst my phone is working. I have run a cable through my house and switched my PC to a wired connection and this no longer has any issues, but any wifi devices randomly drop onto connected but no internet daily and this is only fixed by resetting the wifi connection.

I have spoken to customer services but every time the operator tries a few things then pass me to a new operator and I have to start all over again asking me to reset it and try wired connections etc which is driving me crazy.I

 have used the online test and no issues where found, I have also factory reset the router but this made no difference.

Could it be my hub is faulty? 

Many thanks for reading this

Will