Experience with Pets Best and their coverage of cat scratch fever?

My cat was recently in the emergency with a high fever and lethargy but her tests kept coming back normal. A Fever of Unknown Origin (FUO) panel was done and she finally came back positive for cat stretch fever.

She is an outdoor cat (there are reasons for this and is not the basis for this post) she gets regular topical flea treatment and yet she still got sick.

Now my worry is that pets best will not cover this claim because it’s a flea illness?

Has anyone had experience with this type of claim being approved or had success appealing a denial? Her vet bills are now 4,000+ due to a necessary hospitalization and I’m not sure how I’m going to manage the bill if this is not covered.

Any advice, or tips would be greatly appreciated. Shes still due another course on the correct antibiotics so her bill is only going to go up.