Internet keeps dropping

[#1]

Hi, we got Plusnet back at the start of May and have never had an issues with the internet dropping in and out until now. Normally I don’t mind it too much on my phone but when I’m trying to use my laptop for work it connects to the internet and says connected but no internet and when I connect to the extension it works better but keeps dropping in and out. But I’m quite stuck on what to do as my laptop is essential for my work but it’s not reliable to use anymore with the internet dropping in and out constantly

[#2]

When you say "when I connect to the extension it works better", what do you mean?

Does it work better if the laptop is connected directly to the router by a cable, rather than wifi? (Is the light on the router blue all the time, or are you getting other colours?)

[#3]

We had to buy a wifi extender for our flat as the wifi wasn’t reaching the bedrooms. My laptop can only get wifi if I’m connected to the extension if I connect to just the normal wifi it connects but says no internet. The WiFi has been staying constantly blue it hasn’t been showing any other colours to indicate that there is a problem with the router.