@Modem - My modem kept cutting out and stopping entirely. Support booked a technician for 4 days out but that's a long time to go without.
From the warmth of the modem I wondered if overheating was a problem. I positioned a fan in front of it about 7 hours ago and it's had only one momentary blip since then!
Welcome to the community!
It sounds like the issue is with your modem if you want you can contact customer support and have them process an exchange through a store close to you and hopefully that can get you up and running faster without having to put a fan in front of it.