I'm posting here as an Android user. I have found a solution. I go into my App Settings and force stop Hayday, then clear all data, and then power off and restart my phone. When you load Hayday again, it works but starts you a brand new game. From that screen you can hit the load previous farm option in upper left screen. You then have to log in with your super cell id, enter your email address associated, and they will send you a code to access your farm.