Having worked in this area before, I can confirm that at least back in 2010 there were exactly 2 ships in the Pacific capable of repairing undersea cable breaks. Even in ordinary situations you generally have to wait for weeks in order to schedule them. I think this worry is very low probability, but not necessarily zero.

If there was a massive power spike that somehow damaged multiple repeaters along the ocean floor, it could be weeks to months before those cables could be back in service.

There are satellite links available, but these would be extremely crowded and likely a lot of information deemed unnecessary would be filtered in order to try and give priority to a few important customers.

Under normal circumstances, there is lots of redundancy, so it would require a very large EMP to damage enough of them simultaneously. I agree it sounds like a cover story, but it would be exceedingly difficult for anyone to prove it.

It only takes one high level tech operating under orders from the CEO to manually disable a repeater and say it is damaged. How would anyone else know?