2 Home Laptops can't share files after installation of an Xfinity XB* router/modeum

I had an issue with my router at home and replaced it with an XB8, that's all a 1 for 1 switch. All the WIFI worked fine but my 2 Laptops that I always share files with back and forth can't see each other. Nothing else changed except the router and I spoke with 4 employees at Xfinity and none of them can help, it's like they're saying not my fault. Both are on the same network, user ID's and password are built in them and all I did was swap one router for another yet Xfinity says its not their fault and that theres no one there trained to help and this was after talking to some that said they were a level 2 tech.