I’m sorry to hear of your struggles.
Keep in mind in the future that an insurance claim person’s job is to find any ostensible excuse to deny claims. Never give them more information than they need because it will always be used against you. Telling them something like your lock was unlocked or you have cameras but they didn’t capture anything will always be used against you if they can.
If you can dispute this, I would counter to them that it’s common and easy nowadays for thieves to use jammers and deauth broadcasters which prevent the cameras from uploading security footage to the cloud and claim this is the reason you believe there is no footage during the time they were there
The lock things is weird though. I don’t know how you have it setup, but it should autolock even if they jam it. The only exceptions I know of would be if the battery is dead or you are home and the auto unlock is triggered. I’ve had the locks for years.
You should always have SD cards in the cameras as backup for network issues or jamming.
If you do have SD cards in them, then the footage will still be there, you may just have to remove the card and look it up manually on a computer.
It is a little weird that all of your cameras stopped working at the exact same time. This implies that you either have some kind of an Internet issue (low bandwidth, bad router, low signal, signal interference, etc) or got jammed. I have over 50 Wyze cameras and mine almost always work unless there is a massive public AWS outage.
I know the majority of burglaries are perpetrated by family, friends, or neighbors of someone in the household, and the majority of the them are by teenagers and desperate drug addicts. So there is a good chance it was someone who has been to your house before, which implies they would have known about the cameras and known to use a jammer or deauth tool. So it’s not surprising you don’t have cloud footage. I would really try to counter their fraud conclusion with the jammer and deauth angle if it were me.
I’ve got a question though, what does your lock log show? I struggle to believe it randomly unlocked or didn’t autolock. Does it show they used the front door?
If you have no camera footage, are you sure it wasn’t a family member or the friends of one of your kids or something? That is a common thing.
Either way, I hope you can dispute their conclusion. In the future don’t give them unnecessary details they can use against you. It’s their job to try to deny your claim and save their investors’ profits. They are absolutely not in your side, as we can see.