I am asking for my sister she needs help reinstalling and getting to her level that she was at.

She had tried to open the HP app and it opened to the screen asking her to put in her birthday. She did that and it started the game back at Level 1 on her iPhone. If she goes in on her iPad it shows her at Level 36. She can't seem to get back to that level on her iPhone. She has tried rebooting her phone, removing and reinstalling the app nothing works. Now when she just tried to go in she ended up in a constant loop of it asking for her birthday and saying continue. Help please.