I did not speak to a technical team as I was unable to reach them via live chat in the past seven days consecutively. All I've done actually referred to the suggestions in this forum as many people face exactly this problem. I don't want to go through the call process again anymore honestly I can't handle the long waiting time on the phone and their unhelpful troubleshooting.
I would be grateful if you could advise me with helpful solutions to this problem. My area is new built, the modem is placed right next to my sofa where we use the Internet.