ATT prepaid data plan not working on iPad mini post iOS upgrade

My ATT prepaid data plan is no longer working on iPad mini 5 post the iOS 13.1.2 upgrade. I have reset my network settings, took the SIM card out and put it back in, turned the iPad on and off, updated my credit card and I have been charged for unlimited data service. I see LTE 5G but still can’t surf the web. Any thoughts would be appreciated.