total problem

Jul 23. 2021, I visited AT&T store and new open home internet service. and i asked to install the modem myself, but it was impossible. And at 11 AM on the 26th , a technician came and worked for 2 hours, and he forced the place he wanted, but not the place i wanted, also i did not receive any documents.  first i try open smart home manager, but not working so another technician came to my home and fixed after 1 week.

After that, it's impossible verify credit card and bank account, the reason is network error, and someone control my home internet. so  i visited the store almost every day and i was surprised. there was no one in the records and i installed it myself. and the current modem default device access code is different but internet is working.  when i calling about this issue always 2 line in my home. the most dangerous is someone changed small business  account on 5th of Aug. i live apartment  it's resident zone and contract  with personal account.   i try to  fixed about this issue, it is impossible for various reasons. and my AT&T wireless is working call and massage, but all internet service and verify massage is not working at all almost  for three week.

help me please!!!