logging in app issue

Since I got my phone from t mobile (iPhone 15) I haven't been able to completely login to the app. It just says processing then give a loading wheal and back to processing. I called before and was told that they are updating it. I waited for the update still no change. I made sure my phone is fully updated still no change deleted the app and reinstalled no change. I can login to my account on the website but it won't let me go anywhere but to my account itself no shopping or benefits to look at.  SO I AM WONDERING WHAT IS WRONG WITH YOUR APP AND WEBSITE IT BEEN 2 TO 3 MONTHS!!!!!!!!!!!!!!!!!!!!!!!