While you are waiting for that to arrive you need to remove everything from the tank including the substrate. Replace the substrate with paper towels. This will make it easier to see them and help get rid of them faster. You need to soak your snake daily with a drop of dawn dish soap in the water, and provide a minimalistic set up until they are 100% gone. Perfect temperatures and humidity in the cage will help make your snake more comfortable, but this is going to be stressful for both of you. Mites are a serious problem that can be caused by many things.
This is by no means a comprehensive list of things to do. I'm sure others will post something, do a search on this site for mites, I'm sure you will find tons of good information that way.