Access code USIM9991 and now other troubles.
I have an IPad mini 6th generation. Just bought / upgraded 2/16/22. ATT data plan worked until recently. Invalid Access code USIM9991 when I tried to manage plan or prepay for additional data. Eventually ran out of data. Tried to add more prepaid data through the website login, paid and waited. Took my money but my iPad never received the additional data for the 2 month period, after receiving an email verification. Resetting network connections didn’t work nor starting over deleting the old account and starting again with a new plan. Before I reset to Verizon account, any suggestions? I like the ATT pay as you go plans.