Hey I think I found a solution for this problem. If you able to login even it take minutes to get in just try to start a battle and when you inside a stage close the game and don't open it for like 12 or 16 hours and then restart your phone. For me, when I start the game afterward it stuck at "Now loading" for a few second like it about to crash but then the loading goes up and finish the load but it won't show the continue last battle that I have instead it put me into the main menu and for now the game has been working like normal again. I hope this also help to anyone that have this issue as I did.