Wait, so the router was BEHIND THE FRIDGE? That's not just a bad spot, that's like a fridge is basically a metal box that blocks the signal. I honestly think the bigger issue here is that you gave notice over a router, but the landlord was the one acting crazy. He can't keep a deposit for early termination on a month-to-month lease, that's just not how it works. He would have lost that in any small claims court, and he knows it. Leaving the review was probably the best move. It's not really about the Wi-Fi, it's about the landlord being unreasonable about a tiny request, and that's a red flag for bigger problems down the road.