UPDATE: Okay, after about a week of the same, I realized I was getting thrown out every time I tried to select the last Sim that I created. I started thinking maybe there is something wrong with that Sim or the house location she was living in. (It is the last house built in Sim Springs that a Sim can live in, not the community property.). Since I have way more houses than Sims, I had her visit a different house, in a different neighborhood. I didn’t officially moved her out of her old house, she was just “visiting”. I logged out and back into the game, went to the Sim character select menu, clicked on the last character I made and did not get thrown out! I “officially” moved her into the new house and have been able to play normally ever since. I did contact technical support but all I was told is they are aware of the issue.
I hope this will be a help to others who are having the same issue of getting thrown out of the game and losing progress. I play on iPad Air, latest edition and iOS is fully updated.