This is why it's a great idea to buy travel insurance (they sell some that doesn't include a medical component.) I have a trip happening where the airline has moved one flight by 48 hours. By objecting I was able to get it to just 24 hours moved, and my travel insurance is covering the extra night's stay at the hotel I was supposed to be leaving that day, as well as the change fees for hotels and airlines down the "domino chain" that are affected.
Do whatever you can to get hold of your airline. Email them, call them, message them on FB, @ them on Twitter, until somebody talks to you. (Do this even if you have a travel agent - if you have one get them on the case as well. I was able to get hold of someone at my airline quicker than my agent could, then connected those two by email.) See if your 48 hour change can be a 24 hour change. See if there's a connecting flight that will let you travel on the same day but have it take longer. Interact with them intensively until you've either minimized the impact of the change (eg you won't miss a day's work) or established that you've done all you can. Then if you have travel insurance, make a claim for the costs of the involuntary change.