Wifi connection not working

[Katrina+Mac]

My sky Q mini and booster box are not connecting to the main router. I've tried resetting restarting reconnecting etc but nothing is working. My sky q mini keeps saying its connected then as soon as I got to watch something that is not live it plays up. I try to reconnect but says it can't currently connect. Router booster and sky boxes are all located in correct places as they are where the engineer put them. I'm having this problem alone and feel I'm paying another for a service that I am not getting full use of. 

[Katrina+Mac]

Also the live TV freezes in and out.