It’s disgusting how bad the weather had to be to take a surcharge. It takes more than just a bad review…I’ve been using airport shuttles for a long time now, they are 100% coming whatever the weather (probably even if there is an earthquake) and downtime is initially negotiated (as it is fixed), then there are no surprises. Here is the service I use the last time I went to Chamonix: https://atobtransfer.com/ By the way, they also carry animals, you just need to call ahead and say for the dimensions so that there are no problems with payment.