Router continually trying to connect and failing

My service went live last Tuesday (8th June) and was flawless until midday yesterday when it suddenly cut out. Thinking it was probably only temporary I didn’t think much about it, but as it’s still broken of this morning I thought I’d contact support.
The router’s status symbol is red, and it seems to go through a minute-long cycle of
Broadband light flashing green → Broadband light solid green → Internet light flashing red → Broadband light off completely → and then it goes back to the start, flashing the broadband light green again.

Tried a factory reset and moving it to the master test socket; neither did anything. I have the router logs if those’d help at all.

It seems to have resolved itself naturally about half an hour ago - so nearly 24 hours without internet.

Very strange.

Update: I unplugged the router by mistake when doing some rearranging, and upon turning it back on it’s broken again.

@jake I think your assistance might be needed on this one!