ATT remote sim card lock??

I attempted to lock my sim card to help with "sim_jacking", when I reset my phone to factory defaults I got locked out of my network. Now is asking for A puk code. I wrote everything down so I wouldn't forget. On 2-22-2019 I purchased A phone from walgreens, 37160, went to walmart to activate via display computer or phone, the my attempts were blocked. I then proceeded to the ATT store to get help, the rep stated he couldn't activate the phone for me, denied me access to the displays, and tried to deny me access to the voip phone sitting on the display shelf. It took an hour on the phone with ATT, complete the activation. After activation, the myatt app froze, I was unable to access my prepaid account information. my high speed data was used up in less than an hour. Today I decided to lock my simcard to prevent access, wrote all the changes down, someone changed the pin remotely, this is after attempting to get help about ongoing hate crimes and oppression